diff --git a/.github/workflows/build-and-release.yml b/.github/workflows/build-and-release.yml
index 601bf1c7..7ba3009c 100644
--- a/.github/workflows/build-and-release.yml
+++ b/.github/workflows/build-and-release.yml
@@ -48,7 +48,7 @@ jobs:
         uses: actions/upload-artifact@v7.0.2
         with:
           name: ${{ env.Asset_Name }}.zip
-          path: ./UOFiddler/bin/Release/
+          path: ./UoFiddler/bin/Release/
 
   release:
     name: Release
diff --git a/Ultima/AnimationEdit.cs b/Ultima/AnimationEdit.cs
index 0579b355..a9966dc8 100644
--- a/Ultima/AnimationEdit.cs
+++ b/Ultima/AnimationEdit.cs
@@ -65,6 +65,13 @@ private static void InitializeCache()
         /// </summary>
         public static void Reload()
         {
+            _fileIndex?.Dispose();
+            _fileIndex2?.Dispose();
+            _fileIndex3?.Dispose();
+            _fileIndex4?.Dispose();
+            _fileIndex5?.Dispose();
+            _fileIndex6?.Dispose();
+
             _fileIndex = new FileIndex("Anim.idx", "Anim.mul", 6);
             _fileIndex2 = new FileIndex("Anim2.idx", "Anim2.mul", -1);
             _fileIndex3 = new FileIndex("Anim3.idx", "Anim3.mul", -1);
@@ -262,14 +269,19 @@ public static void LoadFromVD(int fileType, int body, BinaryReader bin)
                 entries[i].Extra = bin.ReadInt32();
             }
 
-            foreach (Entry3D entry in entries)
+            for (int i = 0; i < entries.Length; ++i, ++index)
             {
+                Entry3D entry = entries[i];
                 if ((entry.Lookup > 0) && (entry.Lookup < bin.BaseStream.Length) && (entry.Length > 0))
                 {
                     bin.BaseStream.Seek(entry.Lookup, SeekOrigin.Begin);
                     cache[index] = new AnimIdx(bin, entry.Extra);
                 }
-                ++index;
+                else
+                {
+                    // Empty in the .vd: drop what the body had there, as LoadActionFromVD does.
+                    GetAnimation(fileType, body, i / 5, i % 5).ClearFrames();
+                }
             }
         }
 
@@ -590,26 +602,31 @@ public unsafe Bitmap[] GetFrames()
 
                 var bmp = new Bitmap(width, height, PixelFormat.Format16bppArgb1555);
                 BitmapData bd = bmp.LockBits(new Rectangle(0, 0, width, height), ImageLockMode.WriteOnly, PixelFormat.Format16bppArgb1555);
-                var line = (ushort*)bd.Scan0;
+                var pixels = (ushort*)bd.Scan0;
                 int delta = bd.Stride >> 1;
 
                 int xBase = frame.Center.X - 0x200;
                 int yBase = frame.Center.Y + height - 0x200;
 
-                line += xBase;
-                line += yBase * delta;
-
+                // Runs are clipped to the frame, so a bad header cannot write outside the bitmap.
                 for (int j = 0; j < frame.RawData.Length; ++j)
                 {
                     FrameEdit.Raw raw = frame.RawData[j];
 
-                    ushort* cur = line + (((raw.offsetY) * delta) + ((raw.offsetX) & 0x3FF));
-                    ushort* end = cur + (raw.run);
+                    int y = yBase + raw.offsetY;
+                    if (y < 0 || y >= height)
+                    {
+                        continue;
+                    }
 
-                    int ii = 0;
-                    while (cur < end)
+                    ushort* row = pixels + (y * delta);
+                    int x = xBase + (raw.offsetX & 0x3FF);
+                    for (int k = 0; k < raw.run; ++k, ++x)
                     {
-                        *cur++ = Palette[raw.data[ii++]];
+                        if (x >= 0 && x < width)
+                        {
+                            row[x] = Palette[raw.data[k]];
+                        }
                     }
                 }
 
diff --git a/Ultima/Animations.cs b/Ultima/Animations.cs
index a861c174..ff2e8053 100644
--- a/Ultima/Animations.cs
+++ b/Ultima/Animations.cs
@@ -1,3 +1,4 @@
+using System;
 using System.Drawing;
 using System.Drawing.Imaging;
 using System.IO;
@@ -143,9 +144,15 @@ public static AnimationFrame[] GetAnimation(int body, int action, int direction,
                 _streamBuffer = new byte[length];
             }
 
-            _ = stream.Read(_streamBuffer, 0, length);
+            int read = stream.ReadAtLeast(_streamBuffer.AsSpan(0, length), length, throwOnEndOfStream: false);
 
-            var memoryStream = new MemoryStream(_streamBuffer, false);
+            // Too short to hold a palette and a frame count: decoding it would read stale buffer bytes.
+            if (read < (PaletteCapacity * 2) + 4)
+            {
+                return null;
+            }
+
+            var memoryStream = new MemoryStream(_streamBuffer, 0, read, false);
 
             bool flip = direction > 4;
             AnimationFrame[] frames;
@@ -711,54 +718,46 @@ public unsafe AnimationFrame(ushort[] palette, BinaryReader bin, bool flip)
             var bmp = new Bitmap(width, height, PixelFormat.Format16bppArgb1555);
             BitmapData bd = bmp.LockBits(
                 new Rectangle(0, 0, width, height), ImageLockMode.WriteOnly, PixelFormat.Format16bppArgb1555);
-            var line = (ushort*)bd.Scan0;
+            var pixels = (ushort*)bd.Scan0;
             int delta = bd.Stride >> 1;
 
-            int header;
-
             int xBase = xCenter - 0x200;
             int yBase = (yCenter + height) - 0x200;
 
-            if (!flip)
+            try
             {
-                line += xBase;
-                line += yBase * delta;
-
+                int header;
                 while ((header = bin.ReadInt32()) != 0x7FFF7FFF)
                 {
                     header ^= _doubleXor;
 
-                    ushort* cur = line + ((((header >> 12) & 0x3FF) * delta) + ((header >> 22) & 0x3FF));
-                    ushort* end = cur + (header & 0xFFF);
-                    while (cur < end)
+                    // Runs are clipped to the frame, so a bad header cannot write outside the bitmap.
+                    int y = yBase + ((header >> 12) & 0x3FF);
+                    int x = xBase + ((header >> 22) & 0x3FF);
+                    int run = header & 0xFFF;
+                    bool rowInside = y >= 0 && y < height;
+                    ushort* row = pixels + (y * delta);
+
+                    for (int k = 0; k < run; ++k, ++x)
                     {
-                        *cur++ = palette[bin.ReadByte()];
+                        ushort color = palette[bin.ReadByte()];
+                        if (rowInside && x >= 0 && x < width)
+                        {
+                            row[flip ? width - 1 - x : x] = color;
+                        }
                     }
                 }
             }
-            else
+            finally
             {
-                line -= xBase - width + 1;
-                line += yBase * delta;
-
-                while ((header = bin.ReadInt32()) != 0x7FFF7FFF)
-                {
-                    header ^= _doubleXor;
-
-                    ushort* cur = line + ((((header >> 12) & 0x3FF) * delta) - ((header >> 22) & 0x3FF));
-                    ushort* end = cur - (header & 0xFFF);
-
-                    while (cur > end)
-                    {
-                        *cur-- = palette[bin.ReadByte()];
-                    }
-                }
+                bmp.UnlockBits(bd);
+            }
 
+            if (flip)
+            {
                 xCenter = width - xCenter;
             }
 
-            bmp.UnlockBits(bd);
-
             Center = new Point(xCenter, yCenter);
             Bitmap = bmp;
         }
diff --git a/Ultima/Animdata.cs b/Ultima/Animdata.cs
index b5c23b42..53085fdf 100644
--- a/Ultima/Animdata.cs
+++ b/Ultima/Animdata.cs
@@ -7,15 +7,21 @@ namespace Ultima
 {
     public sealed class Animdata
     {
+        private const int _recordSize = 64 + 4;
+
         private static int[] _header;
         private static byte[] _unknown;
 
+        // Records with a frame count of 0 that still hold data. They are not entries, but Save writes
+        // them back unchanged.
+        private static Dictionary<int, byte[]> _emptyRecords = new Dictionary<int, byte[]>();
+
         public static Dictionary<int, AnimdataEntry> AnimData { get; set; }
 
         /// <summary>
-        /// Entry slots in the loaded file, 8 per chunk.
+        /// Entry slots in the loaded file, 8 per chunk. The last chunk can be short.
         /// </summary>
-        public static int SlotCount => (_header?.Length ?? 0) * 8;
+        public static int SlotCount { get; private set; }
 
         static Animdata()
         {
@@ -28,6 +34,10 @@ static Animdata()
         public static void Initialize()
         {
             AnimData = new Dictionary<int, AnimdataEntry>();
+            _emptyRecords = new Dictionary<int, byte[]>();
+            _header = [];
+            _unknown = null;
+            SlotCount = 0;
 
             string path = Files.GetFilePath("animdata.mul");
             if (path == null)
@@ -35,56 +45,54 @@ public static void Initialize()
                 return;
             }
 
-            using (var fs = new FileStream(path, FileMode.Open, FileAccess.Read, FileShare.Read))
-            using (var bin = new BinaryReader(fs))
+            byte[] file = File.ReadAllBytes(path);
+            var headers = new List<int>();
+            int pos = 0;
+            int id = 0;
+
+            // Chunks are a 4 byte header and 8 records. The last chunk can hold fewer records,
+            // and can end in a part of a record, which is kept as is.
+            while (file.Length - pos >= 4 + _recordSize)
             {
-                unsafe
+                headers.Add(BitConverter.ToInt32(file, pos));
+                pos += 4;
+
+                for (int i = 0; i < 8 && file.Length - pos >= _recordSize; ++i, ++id)
                 {
-                    int id = 0;
-                    int h = 0;
+                    ReadRecord(file, pos, id);
+                    pos += _recordSize;
+                }
+            }
 
-                    _header = new int[bin.BaseStream.Length / (4 + (8 * (64 + 4)))];
+            _header = headers.ToArray();
+            SlotCount = id;
 
-                    while (h < _header.Length)
-                    {
-                        _header[h++] = bin.ReadInt32(); // chunk header
+            if (pos < file.Length)
+            {
+                _unknown = file.AsSpan(pos).ToArray();
+            }
+        }
 
-                        // Read 8 tiles
-                        byte[] buffer = bin.ReadBytes(544);
+        private static void ReadRecord(byte[] file, int pos, int id)
+        {
+            byte frameCount = file[pos + 65];
+            if (frameCount == 0)
+            {
+                if (file.AsSpan(pos, _recordSize).ContainsAnyExcept((byte)0))
+                {
+                    _emptyRecords[id] = file.AsSpan(pos, _recordSize).ToArray();
+                }
 
-                        fixed (byte* buf = buffer)
-                        {
-                            byte* data = buf;
-
-                            for (int i = 0; i < 8; ++i, ++id)
-                            {
-                                sbyte[] frame = new sbyte[64];
-
-                                for (int j = 0; j < 64; ++j)
-                                {
-                                    frame[j] = (sbyte)*data++;
-                                }
-
-                                byte unk = *data++;
-                                byte frameCount = *data++;
-                                byte frameInterval = *data++;
-                                byte frameStart = *data++;
-
-                                if (frameCount > 0)
-                                {
-                                    AnimData[id] = new AnimdataEntry(frame, unk, frameCount, frameInterval, frameStart);
-                                }
-                            }
-                        }
-                    }
+                return;
+            }
 
-                    var remaining = (int)(bin.BaseStream.Length - bin.BaseStream.Position);
-                    if (remaining > 0)
-                    {
-                        _unknown = bin.ReadBytes(remaining);
-                    }
-                }
+            sbyte[] frame = new sbyte[64];
+            for (int j = 0; j < 64; ++j)
+            {
+                frame[j] = (sbyte)file[pos + j];
             }
+
+            AnimData[id] = new AnimdataEntry(frame, file[pos + 64], frameCount, file[pos + 66], file[pos + 67]);
         }
 
         /// <summary>
@@ -100,49 +108,54 @@ public static void Save(string path)
         {
             string fileName = Path.Combine(path, "animdata.mul");
 
+            int maxId = AnimData.Count > 0 ? AnimData.Keys.Max() : -1;
+
+            // Keep the loaded slot count, including a short last chunk. Growing the file rounds it up
+            // to whole chunks, and the partial record that ended the old file no longer fits.
+            int slots = SlotCount;
+            bool grown = maxId >= slots;
+            if (grown)
+            {
+                slots = (maxId + 8) & ~7;
+            }
+
             using (var fs = new FileStream(fileName, FileMode.Create, FileAccess.Write, FileShare.Write))
             using (var bin = new BinaryWriter(fs))
             {
-                int id = 0;
                 int h = 0;
-                int maxId = AnimData.Keys.Max();
-                while (id <= maxId)
+                for (int id = 0; id < slots; ++id)
                 {
-                    int headerChunk = h < _header.Length ? _header[h++] : Random.Shared.Next();
-                    bin.Write(headerChunk);
-                    for (int i = 0; i < 8; ++i, ++id)
+                    if ((id & 7) == 0)
+                    {
+                        int headerChunk = h < _header.Length ? _header[h] : Random.Shared.Next();
+                        ++h;
+                        bin.Write(headerChunk);
+                    }
+
+                    AnimdataEntry animdataEntry = GetAnimData(id);
+                    if (animdataEntry != null)
                     {
-                        AnimdataEntry animdataEntry = GetAnimData(id);
                         for (int j = 0; j < 64; ++j)
                         {
-                            if (animdataEntry != null)
-                            {
-                                bin.Write(animdataEntry.FrameData[j]);
-                            }
-                            else
-                            {
-                                bin.Write((sbyte)0);
-                            }
+                            bin.Write(animdataEntry.FrameData[j]);
                         }
 
-                        if (animdataEntry != null)
-                        {
-                            bin.Write(animdataEntry.Unknown);
-                            bin.Write(animdataEntry.FrameCount);
-                            bin.Write(animdataEntry.FrameInterval);
-                            bin.Write(animdataEntry.FrameStart);
-                        }
-                        else
-                        {
-                            bin.Write((byte)0);
-                            bin.Write((byte)0);
-                            bin.Write((byte)0);
-                            bin.Write((byte)0);
-                        }
+                        bin.Write(animdataEntry.Unknown);
+                        bin.Write(animdataEntry.FrameCount);
+                        bin.Write(animdataEntry.FrameInterval);
+                        bin.Write(animdataEntry.FrameStart);
+                    }
+                    else if (_emptyRecords.TryGetValue(id, out byte[] raw))
+                    {
+                        bin.Write(raw);
+                    }
+                    else
+                    {
+                        bin.Write(new byte[_recordSize]);
                     }
                 }
 
-                if (_unknown != null)
+                if (_unknown != null && !grown)
                 {
                     bin.Write(_unknown);
                 }
diff --git a/Ultima/Art.cs b/Ultima/Art.cs
index a7ba3864..b098d2d9 100644
--- a/Ultima/Art.cs
+++ b/Ultima/Art.cs
@@ -39,8 +39,11 @@ private struct ImageData
         // M3.5: dedup index keyed by xxHash128 of the bitmap pixels. Replaces
         // the previous List<ImageData> + SHA256-bytes-in-each-entry layout,
         // which made CompareSaveImages an O(n²) linear scan.
+        private static readonly object _readLock = new object();
+
         private static Dictionary<UInt128, ImageData> _landImageData;
-        private static Dictionary<UInt128, ImageData> _staticImageData;
+        // Keyed by size as well: the pixel hash alone matches images of different sizes with the same bytes.
+        private static Dictionary<(UInt128 Hash, int Width, int Height), ImageData> _staticImageData;
 
         static Art()
         {
@@ -222,8 +225,15 @@ public static void ReplaceStatic(int index, Bitmap bmp)
         /// </summary>
         /// <param name="index"></param>
         /// <param name="bmp"></param>
+        /// <exception cref="ArgumentException">Thrown when the bitmap is not 44x44</exception>
         public static void ReplaceLand(int index, Bitmap bmp)
         {
+            // Save encodes land as a fixed 44x44 block straight from the bitmap's memory.
+            if (bmp != null && (bmp.Width != 44 || bmp.Height != 44))
+            {
+                throw new ArgumentException($"Land tiles must be 44x44 pixels, got {bmp.Width}x{bmp.Height}.", nameof(bmp));
+            }
+
             index &= 0x3FFF;
             _replaced[index] = bmp;
             _cache.Remove(index);
@@ -311,20 +321,24 @@ public static bool IsValidStatic(int index)
                 return true;
             }
 
-            Stream stream = _fileIndex.Seek(index, out int _, out int _, out bool _);
-
-            if (stream == null)
+            // The file stream is shared; seek and read must not interleave with another thread.
+            lock (_readLock)
             {
-                return false;
-            }
+                Stream stream = _fileIndex.Seek(index, out int _, out int _, out bool _);
 
-            stream.Seek(4, SeekOrigin.Current);
-            stream.ReadExactly(_validBuffer, 0, 4);
+                if (stream == null)
+                {
+                    return false;
+                }
 
-            short width = (short)(_validBuffer[0] | (_validBuffer[1] << 8));
-            short height = (short)(_validBuffer[2] | (_validBuffer[3] << 8));
+                stream.Seek(4, SeekOrigin.Current);
+                stream.ReadExactly(_validBuffer, 0, 4);
 
-            return width > 0 && height > 0;
+                short width = (short)(_validBuffer[0] | (_validBuffer[1] << 8));
+                short height = (short)(_validBuffer[2] | (_validBuffer[3] << 8));
+
+                return width > 0 && height > 0;
+            }
         }
 
         /// <summary>
@@ -384,23 +398,27 @@ public static Bitmap GetLand(int index, out bool patched)
                 return cached;
             }
 
-            Stream stream = _fileIndex.Seek(index, out int length, out int _, out patched);
-            if (stream == null)
+            // The file stream is shared; seek and read must not interleave with another thread.
+            lock (_readLock)
             {
-                return null;
-            }
+                Stream stream = _fileIndex.Seek(index, out int length, out int _, out patched);
+                if (stream == null)
+                {
+                    return null;
+                }
 
-            if (patched)
-            {
-                _patched[index] = true;
-            }
+                if (patched)
+                {
+                    _patched[index] = true;
+                }
 
-            Bitmap bmp = LoadLand(stream, length);
-            if (Files.CacheData && bmp != null)
-            {
-                _cache.Set(index, bmp);
+                Bitmap bmp = LoadLand(stream, length);
+                if (Files.CacheData && bmp != null)
+                {
+                    _cache.Set(index, bmp);
+                }
+                return bmp;
             }
-            return bmp;
         }
 
         // ReSharper disable once UnusedMember.Global
@@ -408,15 +426,19 @@ public static byte[] GetRawLand(int index)
         {
             index &= 0x3FFF;
 
-            Stream stream = _fileIndex.Seek(index, out int length, out int _, out bool _);
-            if (stream == null)
+            // The file stream is shared; seek and read must not interleave with another thread.
+            lock (_readLock)
             {
-                return null;
-            }
+                Stream stream = _fileIndex.Seek(index, out int length, out int _, out bool _);
+                if (stream == null)
+                {
+                    return null;
+                }
 
-            var buffer = new byte[length];
-            stream.ReadExactly(buffer, 0, length);
-            return buffer;
+                var buffer = new byte[length];
+                stream.ReadExactly(buffer, 0, length);
+                return buffer;
+            }
         }
 
         /// <summary>
@@ -459,23 +481,27 @@ public static Bitmap GetStatic(int index, out bool patched, bool checkMaxId = tr
                 return cached;
             }
 
-            Stream stream = _fileIndex.Seek(index, out int length, out int _, out patched);
-            if (stream == null)
+            // The file stream is shared; seek and read must not interleave with another thread.
+            lock (_readLock)
             {
-                return null;
-            }
+                Stream stream = _fileIndex.Seek(index, out int length, out int _, out patched);
+                if (stream == null)
+                {
+                    return null;
+                }
 
-            if (patched)
-            {
-                _patched[index] = true;
-            }
+                if (patched)
+                {
+                    _patched[index] = true;
+                }
 
-            Bitmap bmp = LoadStatic(stream, length);
-            if (Files.CacheData && bmp != null)
-            {
-                _cache.Set(index, bmp);
+                Bitmap bmp = LoadStatic(stream, length);
+                if (Files.CacheData && bmp != null)
+                {
+                    _cache.Set(index, bmp);
+                }
+                return bmp;
             }
-            return bmp;
         }
 
         // ReSharper disable once UnusedMember.Global
@@ -484,15 +510,19 @@ public static byte[] GetRawStatic(int index)
             index = GetLegalItemId(index);
             index += 0x4000;
 
-            Stream stream = _fileIndex.Seek(index, out int length, out int _, out bool _);
-            if (stream == null)
+            // The file stream is shared; seek and read must not interleave with another thread.
+            lock (_readLock)
             {
-                return null;
-            }
+                Stream stream = _fileIndex.Seek(index, out int length, out int _, out bool _);
+                if (stream == null)
+                {
+                    return null;
+                }
 
-            var buffer = new byte[length];
-            stream.ReadExactly(buffer, 0, length);
-            return buffer;
+                var buffer = new byte[length];
+                stream.ReadExactly(buffer, 0, length);
+                return buffer;
+            }
         }
 
         /// <summary>
@@ -524,41 +554,45 @@ public static unsafe bool TryGetStaticPixels(int index, Span<ushort> destination
                 return false;
             }
 
-            Stream stream = _fileIndex.Seek(index, out int length, out _, out patched);
-            if (stream == null)
+            // The file stream is shared; seek and read must not interleave with another thread.
+            lock (_readLock)
             {
-                return false;
-            }
-
-            if (patched)
-            {
-                _patched[index] = true;
-            }
-
-            byte[] buffer = ArrayPool<byte>.Shared.Rent(length);
-            try
-            {
-                stream.ReadExactly(buffer, 0, length);
-
-                ReadOnlySpan<byte> entry = buffer.AsSpan(0, length);
-                if (!TryReadStaticSize(entry, out width, out height))
+                Stream stream = _fileIndex.Seek(index, out int length, out _, out patched);
+                if (stream == null)
                 {
                     return false;
                 }
 
-                if (destination.Length < width * height)
+                if (patched)
                 {
-                    return false;
+                    _patched[index] = true;
                 }
 
-                fixed (ushort* destPtr = destination)
+                byte[] buffer = ArrayPool<byte>.Shared.Rent(length);
+                try
                 {
-                    return DecodeStatic(entry, destPtr, width, height, width);
+                    stream.ReadExactly(buffer, 0, length);
+
+                    ReadOnlySpan<byte> entry = buffer.AsSpan(0, length);
+                    if (!TryReadStaticSize(entry, out width, out height))
+                    {
+                        return false;
+                    }
+
+                    if (destination.Length < width * height)
+                    {
+                        return false;
+                    }
+
+                    fixed (ushort* destPtr = destination)
+                    {
+                        return DecodeStatic(entry, destPtr, width, height, width);
+                    }
+                }
+                finally
+                {
+                    ArrayPool<byte>.Shared.Return(buffer);
                 }
-            }
-            finally
-            {
-                ArrayPool<byte>.Shared.Return(buffer);
             }
         }
 
@@ -582,60 +616,64 @@ public static unsafe bool TryGetLandPixels(int index, Span<ushort> destination,
                 return false;
             }
 
-            Stream stream = _fileIndex.Seek(index, out int length, out _, out patched);
-            if (stream == null || length < LandTileBytes)
-            {
-                return false;
-            }
-
-            if (patched)
+            // The file stream is shared; seek and read must not interleave with another thread.
+            lock (_readLock)
             {
-                _patched[index] = true;
-            }
-
-            byte[] buffer = ArrayPool<byte>.Shared.Rent(length);
-            try
-            {
-                stream.ReadExactly(buffer, 0, length);
+                Stream stream = _fileIndex.Seek(index, out int length, out _, out patched);
+                if (stream == null || length < LandTileBytes)
+                {
+                    return false;
+                }
 
-                destination.Slice(0, 44 * 44).Clear();
+                if (patched)
+                {
+                    _patched[index] = true;
+                }
 
-                fixed (byte* binData = buffer)
-                fixed (ushort* destPtr = destination)
+                byte[] buffer = ArrayPool<byte>.Shared.Rent(length);
+                try
                 {
-                    var bdata = (ushort*)binData;
-                    int xOffset = 21;
-                    int xRun = 2;
-                    ushort* line = destPtr;
+                    stream.ReadExactly(buffer, 0, length);
 
-                    for (int y = 0; y < 22; ++y, --xOffset, xRun += 2, line += 44)
+                    destination.Slice(0, 44 * 44).Clear();
+
+                    fixed (byte* binData = buffer)
+                    fixed (ushort* destPtr = destination)
                     {
-                        ushort* cur = line + xOffset;
-                        ushort* end = cur + xRun;
-                        while (cur < end)
+                        var bdata = (ushort*)binData;
+                        int xOffset = 21;
+                        int xRun = 2;
+                        ushort* line = destPtr;
+
+                        for (int y = 0; y < 22; ++y, --xOffset, xRun += 2, line += 44)
                         {
-                            *cur++ = (ushort)(*bdata++ | 0x8000);
+                            ushort* cur = line + xOffset;
+                            ushort* end = cur + xRun;
+                            while (cur < end)
+                            {
+                                *cur++ = (ushort)(*bdata++ | 0x8000);
+                            }
                         }
-                    }
 
-                    xOffset = 0;
-                    xRun = 44;
-                    for (int y = 0; y < 22; ++y, ++xOffset, xRun -= 2, line += 44)
-                    {
-                        ushort* cur = line + xOffset;
-                        ushort* end = cur + xRun;
-                        while (cur < end)
+                        xOffset = 0;
+                        xRun = 44;
+                        for (int y = 0; y < 22; ++y, ++xOffset, xRun -= 2, line += 44)
                         {
-                            *cur++ = (ushort)(*bdata++ | 0x8000);
+                            ushort* cur = line + xOffset;
+                            ushort* end = cur + xRun;
+                            while (cur < end)
+                            {
+                                *cur++ = (ushort)(*bdata++ | 0x8000);
+                            }
                         }
                     }
-                }
 
-                return true;
-            }
-            finally
-            {
-                ArrayPool<byte>.Shared.Return(buffer);
+                    return true;
+                }
+                finally
+                {
+                    ArrayPool<byte>.Shared.Return(buffer);
+                }
             }
         }
 
@@ -655,18 +693,22 @@ public static bool TryGetStaticDimensions(int index, out int width, out int heig
                 return false;
             }
 
-            Stream stream = _fileIndex.Seek(index, out int length, out _, out _);
-            if (stream == null || length < 8)
+            // The file stream is shared; seek and read must not interleave with another thread.
+            lock (_readLock)
             {
-                return false;
-            }
+                Stream stream = _fileIndex.Seek(index, out int length, out _, out _);
+                if (stream == null || length < 8)
+                {
+                    return false;
+                }
 
-            // Header layout: 4 unknown ushorts then width, height as ushorts at offset 4 and 6.
-            Span<byte> header = stackalloc byte[8];
-            stream.ReadExactly(header);
-            width = header[4] | (header[5] << 8);
-            height = header[6] | (header[7] << 8);
-            return width > 0 && height > 0;
+                // Header layout: 4 unknown ushorts then width, height as ushorts at offset 4 and 6.
+                Span<byte> header = stackalloc byte[8];
+                stream.ReadExactly(header);
+                width = header[4] | (header[5] << 8);
+                height = header[6] | (header[7] << 8);
+                return width > 0 && height > 0;
+            }
         }
 
         public static unsafe void Measure(Bitmap bmp, out int xMin, out int yMin, out int xMax, out int yMax)
@@ -933,7 +975,7 @@ private static unsafe Bitmap LoadLand(Stream stream, int length)
         public static unsafe void Save(string path)
         {
             _landImageData = new Dictionary<UInt128, ImageData>();
-            _staticImageData = new Dictionary<UInt128, ImageData>();
+            _staticImageData = new Dictionary<(UInt128 Hash, int Width, int Height), ImageData>();
 
             string idx = Path.Combine(path, "artidx.mul");
             string mul = Path.Combine(path, "art.mul");
@@ -1044,7 +1086,7 @@ public static unsafe void Save(string path)
                             try
                             {
                                 UInt128 hash = bd.Hash128();
-                                if (_staticImageData.TryGetValue(hash, out ImageData existing))
+                                if (_staticImageData.TryGetValue((hash, bmp.Width, bmp.Height), out ImageData existing))
                                 {
                                     binidx.Write(existing.Position); // lookup
                                     binidx.Write(existing.Length);
@@ -1064,7 +1106,7 @@ public static unsafe void Save(string path)
                                 int width = 0;
                                 for (int i = 0; i < bmp.Height; ++i) // fill lookup
                                 {
-                                    binmul.Write(width);
+                                    binmul.Write((ushort)width);
                                 }
 
                                 for (int y = 0; y < bmp.Height; ++y, line += delta)
@@ -1072,7 +1114,7 @@ public static unsafe void Save(string path)
                                     ushort* cur = line;
                                     width = (int)(binmul.BaseStream.Position - streamLoc) / 2;
                                     binmul.BaseStream.Seek(lookup + (y * 2), SeekOrigin.Begin);
-                                    binmul.Write(width);
+                                    binmul.Write((ushort)width);
                                     binmul.BaseStream.Seek(streamLoc + (width * 2), SeekOrigin.Begin);
                                     int i = 0;
                                     int x = 0;
@@ -1127,7 +1169,7 @@ public static unsafe void Save(string path)
                                 binidx.Write(length);
                                 binidx.Write(0);
 
-                                _staticImageData[hash] = new ImageData
+                                _staticImageData[(hash, bmp.Width, bmp.Height)] = new ImageData
                                 {
                                     Position = start,
                                     Length = length,
diff --git a/Ultima/FileIndex.cs b/Ultima/FileIndex.cs
index fafca347..3604ae68 100644
--- a/Ultima/FileIndex.cs
+++ b/Ultima/FileIndex.cs
@@ -15,11 +15,26 @@ public sealed class FileIndex : IDisposable
         public long IdxLength { get => FileAccessor?.IdxLength ?? 0; }
         public IEntry this[int index]
         {
-            get => FileAccessor[index];
+            get => FileAccessor?[index];
             // Let the accessor cast: it knows whether it stores Entry3D or Entry6D.
-            set => FileAccessor[index] = value;
+            set
+            {
+                if (FileAccessor != null)
+                {
+                    FileAccessor[index] = value;
+                }
+            }
+        }
+
+        private FileIndex()
+        {
         }
 
+        /// <summary>
+        /// An index with no backing file: every entry reads as missing.
+        /// </summary>
+        public static FileIndex CreateEmpty() => new FileIndex();
+
         private readonly Lock _entryWriteLock = new();
 
         /// <summary>
@@ -249,22 +264,22 @@ public FileIndex(string idxFile, string mulFile, int file)
             }
         }
 
-        /// <summary>
-        /// True when the entry carries the high bit that <see cref="IFileAccessor.ApplyPatch"/> sets
-        /// to mark it as coming from verdata.
-        /// </summary>
-        /// <remarks>
-        /// A length of -1 is the "unused entry" filler that real .idx files are padded with, and it
-        /// has that same high bit set. Without the -1 test every unused entry looks like a verdata
-        /// patch of length 0x7FFFFFFF, and the reader then tries to pull that many bytes out of
-        /// <see cref="Verdata.Stream"/> - which, with no verdata.mul present, is Stream.Null.
-        /// A real patch never reaches 0x7FFFFFFF bytes, so the two cases cannot be confused.
-        /// </remarks>
-        private static bool IsVerdataPatched(IEntry e)
-        {
-            return e.Length != -1 && (e.Length & (1 << 31)) != 0;
-        }
-
+        /// <summary>
+        /// True when the entry carries the high bit that <see cref="IFileAccessor.ApplyPatch"/> sets
+        /// to mark it as coming from verdata.
+        /// </summary>
+        /// <remarks>
+        /// A length of -1 is the "unused entry" filler that real .idx files are padded with, and it
+        /// has that same high bit set. Without the -1 test every unused entry looks like a verdata
+        /// patch of length 0x7FFFFFFF, and the reader then tries to pull that many bytes out of
+        /// <see cref="Verdata.Stream"/> - which, with no verdata.mul present, is Stream.Null.
+        /// A real patch never reaches 0x7FFFFFFF bytes, so the two cases cannot be confused.
+        /// </remarks>
+        private static bool IsVerdataPatched(IEntry e)
+        {
+            return e.Length != -1 && (e.Length & (1 << 31)) != 0;
+        }
+
         public Stream Seek(int index, out int length, out int extra, out bool patched)
         {
             if (FileAccessor is null)
@@ -669,6 +684,8 @@ public IEntry GetEntry(int index)
 
     public class UopFileAccessor : IFileAccessor
     {
+        private const int _legacyGumpId = 9834;
+
         public Entry6D[] Index { get; }
 
         public FileStream Stream { get; set; }
@@ -724,6 +741,12 @@ public UopFileAccessor(string path, string uopEntryExtension, int length, int id
                     hashes.TryAdd(hash, i);
                 }
 
+                // Older clients stored gump 9834 under a 7 digit name.
+                if (uopPattern == "gumpartlegacymul" && length > _legacyGumpId)
+                {
+                    hashes.TryAdd(UopUtils.HashFileName($"build/{uopPattern}/{_legacyGumpId:D7}{uopEntryExtension}"), _legacyGumpId);
+                }
+
                 br.BaseStream.Seek(nextBlock, SeekOrigin.Begin);
 
                 // There are no invalid entries in .uop so we have to initialize all entries
@@ -809,6 +832,10 @@ public void ApplyPatch(Entry5D patch)
             Index[patch.Index].Lookup = patch.Lookup;
             Index[patch.Index].Length = patch.Length | (1 << 31);
             Index[patch.Index].Extra = patch.Extra;
+
+            // Verdata payloads are stored uncompressed, whatever the UOP entry they replace used.
+            Index[patch.Index].Flag = CompressionFlag.None;
+            Index[patch.Index].DecompressedLength = patch.Length;
         }
 
         public IEntry GetEntry(int index)
diff --git a/Ultima/Gumps.cs b/Ultima/Gumps.cs
index 239000cb..3910f2d1 100644
--- a/Ultima/Gumps.cs
+++ b/Ultima/Gumps.cs
@@ -101,7 +101,8 @@ public static void Reload()
             }
             catch
             {
-                _fileIndex = null;
+                // An unreadable file loads as no gumps, so reads return nothing instead of throwing.
+                _fileIndex = FileIndex.CreateEmpty();
                 _indexLength = _maxGumpIndex;
                 _cache?.Clear();
                 _cache ??= new LruBitmapCache(Files.CacheCapacityGumps);
diff --git a/Ultima/Light.cs b/Ultima/Light.cs
index 7137023c..042521ac 100644
--- a/Ultima/Light.cs
+++ b/Ultima/Light.cs
@@ -16,6 +16,7 @@ public sealed class Light
         /// </summary>
         public static void Reload()
         {
+            _fileIndex?.Dispose();
             _fileIndex = new FileIndex("lightidx.mul", "light.mul", 100, -1);
             _cache = new Bitmap[100];
             _removed = new bool[100];
@@ -174,9 +175,9 @@ public static unsafe Bitmap GetLight(int index)
                     bmp.UnlockBits(bd);
                 }
 
-                if (!Files.CacheData)
+                if (Files.CacheData)
                 {
-                    return _cache[index] = bmp;
+                    _cache[index] = bmp;
                 }
 
                 return bmp;
diff --git a/Ultima/MultiComponentList.cs b/Ultima/MultiComponentList.cs
index 8911bdce..a599aea8 100644
--- a/Ultima/MultiComponentList.cs
+++ b/Ultima/MultiComponentList.cs
@@ -810,7 +810,7 @@ public MultiComponentList(MTileList[][] newTiles, int count, int width, int heig
                         SortedTiles[counter].OffsetY = (short)(y - _center.Y);
                         SortedTiles[counter].OffsetZ = mTile.Z;
                         SortedTiles[counter].Flags = mTile.Flag;
-                        SortedTiles[counter].Unk1 = 0;
+                        SortedTiles[counter].Unk1 = mTile.Unk1;
 
                         if (SortedTiles[counter].OffsetX < _min.X)
                         {
diff --git a/Ultima/Multis.cs b/Ultima/Multis.cs
index d805c6e3..ed2c2a0e 100644
--- a/Ultima/Multis.cs
+++ b/Ultima/Multis.cs
@@ -66,6 +66,7 @@ public enum ImportType
         /// </summary>
         public static void Reload()
         {
+            _fileIndex?.Dispose();
             _fileIndex = new FileIndex("Multi.idx", "Multi.mul", MaximumMultiIndex, 14);
             _components = new MultiComponentList[MaximumMultiIndex];
             ReloadUop();
diff --git a/Ultima/RadarCol.cs b/Ultima/RadarCol.cs
index b37377ef..31990b20 100644
--- a/Ultima/RadarCol.cs
+++ b/Ultima/RadarCol.cs
@@ -8,6 +8,9 @@ namespace Ultima
 {
     public sealed class RadarCol
     {
+        // 0x4000 land colors followed by one color per item id up to 0xFFFF.
+        private const int _maxColorIndex = 0x4000 + 0x10000 - 1;
+
         static RadarCol()
         {
             Initialize();
@@ -84,10 +87,11 @@ public static void ImportFromCSV(string fileName)
                 return;
             }
 
+            // Rows update the loaded table; ids past its end grow it.
+            var colors = (ushort[])(Colors ?? []).Clone();
+
             using (var sr = new StreamReader(fileName))
             {
-                int count = 0;
-
                 while (sr.ReadLine() is { } line)
                 {
                     line = line.Trim();
@@ -102,63 +106,38 @@ public static void ImportFromCSV(string fileName)
                         continue;
                     }
 
-                    ++count;
-                }
-
-                Colors = new ushort[count];
-            }
-
-            using (var sr = new StreamReader(fileName))
-            {
-                while (sr.ReadLine() is { } line)
-                {
-                    line = line.Trim();
-
-                    if (line.Length == 0 || line.StartsWith("#"))
+                    string[] split = line.Split(';');
+                    if (split.Length < 2 || !TryConvertStringToInt(split[0], out int id) || !TryConvertStringToInt(split[1], out int color))
                     {
                         continue;
                     }
 
-                    if (line.StartsWith("ID;"))
+                    if (id < 0 || id > _maxColorIndex)
                     {
                         continue;
                     }
 
-                    try
-                    {
-                        string[] split = line.Split(';');
-                        if (split.Length < 2)
-                        {
-                            continue;
-                        }
-
-                        int id = ConvertStringToInt(split[0]);
-                        int color = ConvertStringToInt(split[1]);
-                        Colors[id] = (ushort)color;
-                    }
-                    catch
+                    if (id >= colors.Length)
                     {
-                        // TODO: ignored?
-                        // ignored
+                        Array.Resize(ref colors, id + 1);
                     }
+
+                    colors[id] = (ushort)color;
                 }
             }
+
+            Colors = colors;
         }
 
-        private static int ConvertStringToInt(string text)
+        private static bool TryConvertStringToInt(string text, out int result)
         {
-            int result;
-            if (text.Contains("0x"))
-            {
-                string convert = text.Replace("0x", "");
-                int.TryParse(convert, NumberStyles.HexNumber, null, out result);
-            }
-            else
+            text = text.Trim();
+            if (text.StartsWith("0x", StringComparison.OrdinalIgnoreCase))
             {
-                int.TryParse(text, NumberStyles.Integer, null, out result);
+                return int.TryParse(text.AsSpan(2), NumberStyles.HexNumber, CultureInfo.InvariantCulture, out result);
             }
 
-            return result;
+            return int.TryParse(text, NumberStyles.Integer, CultureInfo.InvariantCulture, out result);
         }
     }
 }
diff --git a/Ultima/Skills.cs b/Ultima/Skills.cs
index 8d13a160..9278889d 100644
--- a/Ultima/Skills.cs
+++ b/Ultima/Skills.cs
@@ -40,6 +40,7 @@ public static List<SkillInfo> SkillEntries
         /// </summary>
         public static void Reload()
         {
+            _fileIndex?.Dispose();
             _fileIndex = new FileIndex("skills.idx", "skills.mul", 16);
             _skillEntries = new List<SkillInfo>();
             for (int i = 0; i < _fileIndex.IndexLength; ++i)
@@ -106,9 +107,11 @@ public static void Save(string path)
             using (var binidx = new BinaryWriter(fsidx))
             using (var binmul = new BinaryWriter(fsmul))
             {
-                for (int i = 0; i < _fileIndex.IndexLength; ++i)
+                List<SkillInfo> entries = SkillEntries;
+                long count = System.Math.Max(_fileIndex.IndexLength, entries.Count);
+                for (int i = 0; i < count; ++i)
                 {
-                    SkillInfo skill = (i < _skillEntries.Count) ? _skillEntries[i] : null;
+                    SkillInfo skill = (i < entries.Count) ? entries[i] : null;
                     if (skill == null)
                     {
                         binidx.Write(-1); // lookup
diff --git a/Ultima/Sound.cs b/Ultima/Sound.cs
index 109f28b0..f1851d79 100644
--- a/Ultima/Sound.cs
+++ b/Ultima/Sound.cs
@@ -47,6 +47,7 @@ public static void Initialize()
         {
             _cache = new UoSound[0xFFF];
             _removed = new bool[0xFFF];
+            _fileIndex?.Dispose();
             _fileIndex = new FileIndex("soundidx.mul", "sound.mul", "soundLegacyMUL.uop", 0xFFF, 8, ".dat", -1, false);
             var reg = new Regex(@"(\d{1,4}) \x7B(\d{1,4})\x7D (\d{1,3})", RegexOptions.Compiled);
 
@@ -103,7 +104,7 @@ public static UoSound GetSound(int soundId, out bool translated)
                 return null;
             }
 
-            if (_removed[soundId])
+            if (soundId >= _removed.Length || _removed[soundId])
             {
                 return null;
             }
@@ -115,7 +116,7 @@ public static UoSound GetSound(int soundId, out bool translated)
 
             Stream stream = _fileIndex.Seek(soundId, out int length, out int _, out bool _);
 
-            if (_fileIndex[soundId].Lookup < 0 || length <= 0)
+            if ((_fileIndex[soundId]?.Lookup ?? -1) < 0 || length <= 0)
             {
                 if (!_translations.TryGetValue(soundId, out soundId))
                 {
@@ -126,7 +127,7 @@ public static UoSound GetSound(int soundId, out bool translated)
                 stream = _fileIndex.Seek(soundId, out length, out int _, out bool _);
             }
 
-            if (stream == null)
+            if (stream == null || length < _mulNameLength)
             {
                 return null;
             }
@@ -208,7 +209,7 @@ public static bool IsValidSound(int soundId, out string name, out bool translate
                 return false;
             }
 
-            if (_removed[soundId])
+            if (soundId >= _removed.Length || _removed[soundId])
             {
                 return false;
             }
@@ -221,7 +222,7 @@ public static bool IsValidSound(int soundId, out string name, out bool translate
 
             Stream stream = _fileIndex.Seek(soundId, out int length, out _, out _);
 
-            if (_fileIndex[soundId].Lookup < 0 || length <= 0)
+            if ((_fileIndex[soundId]?.Lookup ?? -1) < 0 || length <= 0)
             {
                 if (!_translations.TryGetValue(soundId, out soundId))
                 {
@@ -230,10 +231,10 @@ public static bool IsValidSound(int soundId, out string name, out bool translate
 
                 translated = true;
 
-                stream = _fileIndex.Seek(soundId, out _, out _, out _);
+                stream = _fileIndex.Seek(soundId, out length, out _, out _);
             }
 
-            if (stream == null)
+            if (stream == null || length < _mulNameLength)
             {
                 return false;
             }
@@ -261,7 +262,7 @@ public static double GetSoundLength(int soundId)
                 return 0;
             }
 
-            if (_removed[soundId])
+            if (soundId >= _removed.Length || _removed[soundId])
             {
                 return 0;
             }
@@ -276,7 +277,7 @@ public static double GetSoundLength(int soundId)
             else
             {
                 Stream stream = _fileIndex.Seek(soundId, out int length, out int _, out bool _);
-                if (_fileIndex[soundId].Lookup < 0 || length <= 0)
+                if ((_fileIndex[soundId]?.Lookup ?? -1) < 0 || length <= 0)
                 {
                     if (!_translations.TryGetValue(soundId, out soundId))
                     {
@@ -286,7 +287,7 @@ public static double GetSoundLength(int soundId)
                     stream = _fileIndex.Seek(soundId, out length, out int _, out bool _);
                 }
 
-                if (stream == null)
+                if (stream == null || length < _mulNameLength)
                 {
                     return 0;
                 }
diff --git a/Ultima/SpeechList.cs b/Ultima/SpeechList.cs
index 65af5137..b59a3814 100644
--- a/Ultima/SpeechList.cs
+++ b/Ultima/SpeechList.cs
@@ -11,8 +11,6 @@ public sealed class SpeechList
     {
         public static List<SpeechEntry> Entries { get; private set; }
 
-        private static readonly byte[] _buffer = new byte[128];
-
         static SpeechList()
         {
             Initialize();
@@ -42,16 +40,11 @@ public static void Initialize()
                 while (bin.BaseStream.Length != bin.BaseStream.Position)
                 {
                     var id = BinaryPrimitives.ReverseEndianness(bin.ReadInt16());
-                    var length = BinaryPrimitives.ReverseEndianness(bin.ReadInt16());
-
-                    if (length > 128)
-                    {
-                        length = 128;
-                    }
+                    int length = BinaryPrimitives.ReverseEndianness(bin.ReadUInt16());
 
-                    _ = bin.Read(_buffer, 0, length);
+                    byte[] text = bin.ReadBytes(length);
 
-                    string keyword = Encoding.UTF8.GetString(_buffer, 0, length);
+                    string keyword = Encoding.UTF8.GetString(text);
 
                     Entries.Add(new SpeechEntry(id, keyword, order));
 
@@ -75,7 +68,7 @@ public static void SaveSpeechList(string fileName)
                 {
                     bin.Write(BinaryPrimitives.ReverseEndianness(entry.Id));
                     byte[] utf8String = Encoding.UTF8.GetBytes(entry.KeyWord);
-                    var length = (short)utf8String.Length;
+                    var length = (ushort)utf8String.Length;
                     bin.Write(BinaryPrimitives.ReverseEndianness(length));
                     bin.Write(utf8String);
                 }
diff --git a/Ultima/Textures.cs b/Ultima/Textures.cs
index 0814803d..f5658248 100644
--- a/Ultima/Textures.cs
+++ b/Ultima/Textures.cs
@@ -30,6 +30,7 @@ private struct Checksums
         /// </summary>
         public static void Reload()
         {
+            _fileIndex?.Dispose();
             _fileIndex = new FileIndex("Texidx.mul", "Texmaps.mul", 0x4000, 10);
             _cache = new Bitmap[0x4000];
             _removed = new bool[0x4000];
@@ -57,8 +58,15 @@ public static void Remove(int index)
         /// </summary>
         /// <param name="index"></param>
         /// <param name="bmp"></param>
+        /// <exception cref="ArgumentException">Thrown when the bitmap is not 64x64 or 128x128</exception>
         public static void Replace(int index, Bitmap bmp)
         {
+            // Save writes the raw pixels and flags the size as 64 or 128; other sizes would be misread.
+            if (bmp != null && !((bmp.Width == 64 && bmp.Height == 64) || (bmp.Width == 128 && bmp.Height == 128)))
+            {
+                throw new ArgumentException($"Textures must be 64x64 or 128x128 pixels, got {bmp.Width}x{bmp.Height}.", nameof(bmp));
+            }
+
             _cache[index] = bmp;
             _removed[index] = false;
             _patched.Remove(index);
diff --git a/Ultima/TileMatrix.cs b/Ultima/TileMatrix.cs
index f6972a02..fb10f98a 100644
--- a/Ultima/TileMatrix.cs
+++ b/Ultima/TileMatrix.cs
@@ -361,19 +361,29 @@ private unsafe HuedTile[][][] ReadStaticBlock(int x, int y)
         private void ReadUOPFiles(string pattern)
         {
             UOPFiles = MapUopReader.ReadEntryTable(_map, pattern);
+
+            _uopFullChunk = 0;
+            foreach (MapUopEntry t in UOPFiles)
+            {
+                _uopFullChunk = Math.Max(_uopFullChunk, t.Length);
+            }
         }
 
+        private long _uopFullChunk;
+
         private long CalculateOffsetFromUOP(long offset)
         {
             long pos = 0;
 
+            // An absent chunk still covers its blocks: give it the size of a full chunk so the blocks
+            // after it keep their place, and read the ones inside it as empty.
             foreach (MapUopEntry t in UOPFiles)
             {
-                long currentPosition = pos + t.Length;
+                long currentPosition = pos + (t.IsPresent ? t.Length : _uopFullChunk);
 
                 if (offset < currentPosition)
                 {
-                    return t.Offset + (offset - pos);
+                    return t.IsPresent ? t.Offset + (offset - pos) : UOPLength;
                 }
 
                 pos = currentPosition;
diff --git a/Ultima/TileMatrixPatch.cs b/Ultima/TileMatrixPatch.cs
index dcfdce36..5de6fcc2 100644
--- a/Ultima/TileMatrixPatch.cs
+++ b/Ultima/TileMatrixPatch.cs
@@ -165,6 +165,13 @@ private int PatchLand(TileMatrix matrix, string dataPath, string indexPath)
                     int x = blockId / matrix.BlockHeight;
                     int y = blockId % matrix.BlockHeight;
 
+                    // A diff for a block outside the configured map size is skipped, not applied.
+                    if (blockId < 0 || x >= matrix.BlockWidth)
+                    {
+                        fsData.Seek(4 + (64 * 3), SeekOrigin.Current);
+                        continue;
+                    }
+
                     fsData.Seek(4, SeekOrigin.Current);
 
                     var tiles = new Tile[64];
@@ -216,6 +223,12 @@ private int PatchStatics(TileMatrix matrix, string dataPath, string indexPath, s
 
                     lookupReader.ReadInt32(); // Extra
 
+                    // A diff for a block outside the configured map size is skipped, not applied.
+                    if (blockId < 0 || blockX >= matrix.BlockWidth)
+                    {
+                        continue;
+                    }
+
                     if (offset < 0 || length <= 0)
                     {
                         if (StaticBlocks[blockX] == null)
diff --git a/Ultima/Uop/LegacyMulFileConverter.cs b/Ultima/Uop/LegacyMulFileConverter.cs
index fe3c7d2b..c9e81d19 100644
--- a/Ultima/Uop/LegacyMulFileConverter.cs
+++ b/Ultima/Uop/LegacyMulFileConverter.cs
@@ -357,14 +357,10 @@ private static void WriteUop(string inFile, string inFileIdx, string outFile, Fi
                             entryHeader = BuildEntryHeader(entryHeaderTimestamp);
                         }
 
-                        // hash 906142efe9fdb38a, which is file 0009834.tga (and no others, as 7.0.59.5) use a different name format (7 digits instead of 8);
-                        //  if in newer versions more of these files will have adopted that format, someone should update this list of exceptions
-                        //  (even if this seems so much like a typo from someone from the UO development team :P)
-                        if ((type == FileType.GumpartLegacyMul) && (idxEntries[j].Id == 9834))
-                        {
-                            identifier = HashLittle2(string.Format(hashFormat[1], idxEntries[j].Id));
-                        }
-                        else if (type == FileType.MultiCollection && idxEntries[j].Id == _housingBinSentinelId)
+                        // Some older clients stored gump 9834 as 0009834.tga (7 digits). Current clients use
+                        // 8 digits for every gumpart entry, and that is the only name the reader looks up
+                        // first, so always write 8 digits. FromUop and FileIndex still accept the old name.
+                        if (type == FileType.MultiCollection && idxEntries[j].Id == _housingBinSentinelId)
                         {
                             identifier = _housingBinIdentifier;
                         }
diff --git a/Ultima/Uop/MapUopReader.cs b/Ultima/Uop/MapUopReader.cs
index 36c09f08..f17b784c 100644
--- a/Ultima/Uop/MapUopReader.cs
+++ b/Ultima/Uop/MapUopReader.cs
@@ -150,13 +150,29 @@ public static MapUopEntry[] ReadEntryTable(Stream stream, string pattern)
         /// Total payload bytes the container holds. Divided by 196 this is the number of map blocks
         /// it carries, which is normally one more than the facet actually has.
         /// </summary>
+        /// <remarks>
+        /// An absent chunk before the last present one counts as a full chunk, as the reader in
+        /// TileMatrix addresses it. Absent chunks at the end add nothing.
+        /// </remarks>
         public static long TotalPayloadLength(MapUopEntry[] entries)
         {
+            int fullChunk = 0;
+            int lastPresent = -1;
+
+            for (int i = 0; i < entries.Length; i++)
+            {
+                if (entries[i].IsPresent)
+                {
+                    fullChunk = Math.Max(fullChunk, entries[i].Length);
+                    lastPresent = i;
+                }
+            }
+
             long total = 0;
 
-            foreach (MapUopEntry entry in entries)
+            for (int i = 0; i <= lastPresent; i++)
             {
-                total += entry.Length;
+                total += entries[i].IsPresent ? entries[i].Length : fullChunk;
             }
 
             return total;
diff --git a/UoFiddler.Controls/Classes/Utils.cs b/UoFiddler.Controls/Classes/Utils.cs
index 9ee7c287..bb2bcda0 100644
--- a/UoFiddler.Controls/Classes/Utils.cs
+++ b/UoFiddler.Controls/Classes/Utils.cs
@@ -86,6 +86,17 @@ public static string FormatExportId(int id)
                 : id.ToString();
         }
 
+        /// <summary>
+        /// <see cref="ConvertBmp"/> for callers that replace their bitmap with the result: the input is
+        /// disposed, since ConvertBmp always returns a new bitmap.
+        /// </summary>
+        public static Bitmap ConvertBmpAndDispose(Bitmap bmp)
+        {
+            Bitmap converted = ConvertBmp(bmp);
+            bmp.Dispose();
+            return converted;
+        }
+
         public static unsafe Bitmap ConvertBmp(Bitmap bmp)
         {
             BitmapData bd = bmp.LockBits(new Rectangle(0, 0, bmp.Width, bmp.Height), ImageLockMode.ReadOnly, PixelFormat.Format16bppArgb1555);
diff --git a/UoFiddler.Controls/Forms/AnimationEditForm.cs b/UoFiddler.Controls/Forms/AnimationEditForm.cs
index ae083ada..32f1c150 100644
--- a/UoFiddler.Controls/Forms/AnimationEditForm.cs
+++ b/UoFiddler.Controls/Forms/AnimationEditForm.cs
@@ -13,6 +13,7 @@
 using System.Collections.Generic;
 using System.Drawing;
 using System.Drawing.Imaging;
+using System.Globalization;
 using System.IO;
 using System.Linq;
 using System.Windows.Forms;
@@ -1433,11 +1434,11 @@ private void OnClickAdd(object sender, EventArgs e)
                                 using (var bmpTemp = new Bitmap(fileName))
                                 {
                                     // Copying a GIF keeps only its first frame
-                                    Bitmap bitmap = fileName.Contains(".gif") ? bmpTemp : new Bitmap(bmpTemp);
+                                    Bitmap bitmap = fileName.EndsWith(".gif", StringComparison.OrdinalIgnoreCase) ? bmpTemp : new Bitmap(bmpTemp);
 
-                                    if (fileName.Contains(".bmp") || fileName.Contains(".tiff") ||
-                                        fileName.Contains(".png") || fileName.Contains(".jpeg") ||
-                                        fileName.Contains(".jpg"))
+                                    if (fileName.EndsWith(".bmp", StringComparison.OrdinalIgnoreCase) || fileName.EndsWith(".tiff", StringComparison.OrdinalIgnoreCase) ||
+                                        fileName.EndsWith(".png", StringComparison.OrdinalIgnoreCase) || fileName.EndsWith(".jpeg", StringComparison.OrdinalIgnoreCase) ||
+                                        fileName.EndsWith(".jpg", StringComparison.OrdinalIgnoreCase))
                                     {
                                         bitmap = ConvertBmpAnim(bitmap, (int)numericUpDownRed.Value, (int)numericUpDownGreen.Value, (int)numericUpDownBlue.Value);
 
@@ -1451,7 +1452,7 @@ private void OnClickAdd(object sender, EventArgs e)
                                     }
 
                                     //Gif Especial Properties
-                                    if (fileName.Contains(".gif"))
+                                    if (fileName.EndsWith(".gif", StringComparison.OrdinalIgnoreCase))
                                     {
                                         FrameDimension dimension = new FrameDimension(bitmap.FrameDimensionsList[0]);
 
@@ -1651,14 +1652,16 @@ private void OnClickImportPalette(object sender, EventArgs e)
                             continue;
                         }
 
-                        i++;
-
                         if (i >= Animations.PaletteCapacity)
                         {
                             break;
                         }
 
-                        palette[i] = ushort.Parse(line);
+                        if (!ushort.TryParse(line, NumberStyles.Integer, CultureInfo.InvariantCulture, out palette[i]))
+                        {
+                            MessageBox.Show($"Invalid palette value \"{line}\".", "Import Palette", MessageBoxButtons.OK, MessageBoxIcon.Error);
+                            return;
+                        }
 
                         // My Soulblighter Modification
                         // Convert color 0,0,0 to 0,0,8
@@ -1668,6 +1671,8 @@ private void OnClickImportPalette(object sender, EventArgs e)
                             palette[i] = 32769;
                         }
                         // End of Soulblighter Modification
+
+                        i++;
                     }
 
                     edit.ReplacePalette(palette);
@@ -2308,7 +2313,7 @@ private void AddFilesAllDirections(OpenFileDialog dialog)
                 if (edit != null)
                 {
                     // Gif Especial Properties
-                    if (dialog.FileNames[w].Contains(".gif"))
+                    if (dialog.FileNames[w].EndsWith(".gif", StringComparison.OrdinalIgnoreCase))
                     {
                         // dialog.Filename replaced by dialog.FileNames[w]
                         using (Bitmap bitmap = new Bitmap(dialog.FileNames[w]))
@@ -2542,7 +2547,7 @@ private void AddSelectedFiles(OpenFileDialog dialog, Color customConvert)
 
                 // TODO: fix checking file extension
                 // Gif Especial Properties
-                if (!dialog.FileNames[w].Contains(".gif"))
+                if (!dialog.FileNames[w].EndsWith(".gif", StringComparison.OrdinalIgnoreCase))
                 {
                     continue;
                 }
@@ -2953,7 +2958,7 @@ private void AddWithCanvasToolStripMenuItem_Click(object sender, EventArgs e)
 
                                 // TODO: fix checking file extension
                                 // Gif Especial Properties
-                                if (!dialog.FileNames[w].Contains(".gif"))
+                                if (!dialog.FileNames[w].EndsWith(".gif", StringComparison.OrdinalIgnoreCase))
                                 {
                                     continue;
                                 }
@@ -3238,7 +3243,7 @@ private void AddDirectionsAddWithCanvasUniqueImageToolStripMenuItem_Click(object
                             if (edit != null)
                             {
                                 // Gif Especial Properties
-                                if (dialog.FileName.Contains(".gif"))
+                                if (dialog.FileName.EndsWith(".gif", StringComparison.OrdinalIgnoreCase))
                                 {
                                     using (Bitmap bmpTemp = new Bitmap(dialog.FileName))
                                     using (MemoryStream ms = new MemoryStream())
@@ -3924,7 +3929,7 @@ private void AllDirectionsAddWithCanvasKRFrameEditorColorCorrectorToolStripMenuI
                             if (edit != null)
                             {
                                 //Gif Especial Properties
-                                if (dialog.FileName.Contains(".gif"))
+                                if (dialog.FileName.EndsWith(".gif", StringComparison.OrdinalIgnoreCase))
                                 {
                                     using (Bitmap bmpTemp = new Bitmap(dialog.FileName))
                                     using (MemoryStream ms = new MemoryStream())
diff --git a/UoFiddler.Controls/UserControls/AnimDataControl.cs b/UoFiddler.Controls/UserControls/AnimDataControl.cs
index 7e0ad8ce..13e3b374 100644
--- a/UoFiddler.Controls/UserControls/AnimDataControl.cs
+++ b/UoFiddler.Controls/UserControls/AnimDataControl.cs
@@ -37,6 +37,7 @@ public AnimDataControl()
 
         private static AnimDataControl _refMarker;
         private static bool _loaded;
+        private bool _eventsSubscribed;
         private Animdata.AnimdataEntry _selAnimdataEntry;
         private int _currentSelect;
         private int _currentFrame;
@@ -246,18 +247,24 @@ private void OnLoad(object sender, EventArgs e)
 
                 treeView1.EndUpdate();
 
+                // Loaded before the first selection, so CurrentSelect fills the frame list and points
+                // the editor at an entry of the file that was just read.
+                _loaded = true;
+                _currentSelect = -1;
+                _selAnimdataEntry = null;
+                treeViewFrames.Nodes.Clear();
+
                 if (treeView1.Nodes.Count > 0)
                 {
                     treeView1.SelectedNode = treeView1.Nodes[0];
-                    _currentSelect = (int)treeView1.Nodes[0].Tag;
+                    CurrentSelect = (int)treeView1.Nodes[0].Tag;
                 }
 
-                if (!_loaded)
+                if (!_eventsSubscribed)
                 {
                     ControlEvents.FilePathChangeEvent += OnFilePathChangeEvent;
+                    _eventsSubscribed = true;
                 }
-
-                _loaded = true;
             }
         }
 
@@ -495,7 +502,21 @@ private void OnClickAdd(object sender, EventArgs e)
                 return;
             }
 
-            _selAnimdataEntry.FrameData[_selAnimdataEntry.FrameCount] = (sbyte)(index - CurrentSelect);
+            // A record holds 64 frames, each stored as a signed byte offset from the base graphic.
+            if (_selAnimdataEntry.FrameCount >= _selAnimdataEntry.FrameData.Length)
+            {
+                MessageBox.Show($"An entry can hold at most {_selAnimdataEntry.FrameData.Length} frames.", "Add Frame", MessageBoxButtons.OK, MessageBoxIcon.Warning);
+                return;
+            }
+
+            int offset = index - CurrentSelect;
+            if (offset < sbyte.MinValue || offset > sbyte.MaxValue)
+            {
+                MessageBox.Show($"Frames must be within {sbyte.MinValue} to {sbyte.MaxValue} ids of the base graphic.", "Add Frame", MessageBoxButtons.OK, MessageBoxIcon.Warning);
+                return;
+            }
+
+            _selAnimdataEntry.FrameData[_selAnimdataEntry.FrameCount] = (sbyte)offset;
             _selAnimdataEntry.FrameCount++;
 
             TreeNode node = new TreeNode
diff --git a/UoFiddler.Controls/UserControls/ClilocControl.cs b/UoFiddler.Controls/UserControls/ClilocControl.cs
index 794489d5..8150f2bf 100644
--- a/UoFiddler.Controls/UserControls/ClilocControl.cs
+++ b/UoFiddler.Controls/UserControls/ClilocControl.cs
@@ -390,6 +390,7 @@ private void OnClick_DeleteEntry(object sender, EventArgs e)
             }
 
             _cliloc.Entries.RemoveAt(dataGridView1.SelectedCells[0].OwningRow.Index);
+            _source.ResetBindings(false);
             dataGridView1.Invalidate();
             Options.ChangedUltimaClass["CliLoc"] = true;
         }
@@ -510,6 +511,7 @@ public void AddEntry(int number)
                 {
                     _cliloc.Entries.Insert(index, new StringEntry(number, "", StringEntry.CliLocFlag.Custom));
 
+                    _source.ResetBindings(false);
                     dataGridView1.Invalidate();
                     dataGridView1.Rows[index].Selected = true;
                     dataGridView1.FirstDisplayedScrollingRowIndex = index;
@@ -591,14 +593,17 @@ private void OnClickImportCSV(object sender, EventArgs e)
 
                         try
                         {
-                            string[] split = line.Split(';');
-                            if (split.Length < 3)
+                            // Number;Text;Flag - the text itself can contain ';', so it is everything
+                            // between the first and the last separator.
+                            int first = line.IndexOf(';');
+                            int last = line.LastIndexOf(';');
+                            if (first < 0 || last <= first)
                             {
                                 continue;
                             }
 
-                            int id = int.Parse(split[0].Trim());
-                            string text = split[1].Trim();
+                            int id = int.Parse(line.AsSpan(0, first).Trim());
+                            string text = line.Substring(first + 1, last - first - 1).Trim();
 
                             int index = 0;
                             bool handled = false;
diff --git a/UoFiddler.Controls/UserControls/GumpControl.cs b/UoFiddler.Controls/UserControls/GumpControl.cs
index 64b76262..44012df1 100644
--- a/UoFiddler.Controls/UserControls/GumpControl.cs
+++ b/UoFiddler.Controls/UserControls/GumpControl.cs
@@ -50,6 +50,7 @@ private sealed record GumpEntry(string Name, string[] Tags);
 
         private static GumpControl _refMarker;
         private bool _loaded;
+        private bool _eventsSubscribed;
         private bool _showFreeSlots;
         private Dictionary<int, GumpEntry> _gumpEntries = new();
         private string _activeNameFilter = string.Empty;
@@ -222,11 +223,13 @@ protected override void OnLoad(EventArgs e)
                 PopulateListBox(true);
                 LoadGumpXml();
 
-                if (!_loaded)
+                // Reload clears _loaded, so a separate flag keeps the handlers from being added twice.
+                if (!_eventsSubscribed)
                 {
                     ControlEvents.FilePathChangeEvent += OnFilePathChangeEvent;
                     ControlEvents.GumpChangeEvent += OnGumpChangeEvent;
                     ControlEvents.PreviewBackgroundColorChangeEvent += OnPreviewBackgroundColorChanged;
+                    _eventsSubscribed = true;
                 }
 
                 _loaded = true;
@@ -705,9 +708,9 @@ private void OnClickReplace(object sender, EventArgs e)
                 {
                     Bitmap bitmap = new Bitmap(bmpTemp);
 
-                    if (dialog.FileName.Contains(".bmp"))
+                    if (dialog.FileName.EndsWith(".bmp", StringComparison.OrdinalIgnoreCase))
                     {
-                        bitmap = Utils.ConvertBmp(bitmap);
+                        bitmap = Utils.ConvertBmpAndDispose(bitmap);
                     }
 
                     int i = SelectedGumpId;
@@ -805,7 +808,7 @@ private void OnClickFindFree(object sender, EventArgs e)
         private void OnTextChanged_InsertAt(object sender, EventArgs e)
         {
             Color invalidColor = Options.DarkMode ? Color.OrangeRed : Color.Red;
-            if (Utils.ConvertStringToInt(InsertText.Text, out int index, 0, Gumps.GetCount()))
+            if (Utils.ConvertStringToInt(InsertText.Text, out int index, 0, Gumps.GetCount() - 1))
             {
                 InsertText.ForeColor = Gumps.IsValidIndex(index) ? invalidColor : SystemColors.ControlText;
             }
@@ -822,7 +825,7 @@ private void OnKeydown_InsertText(object sender, KeyEventArgs e)
                 return;
             }
 
-            if (!Utils.ConvertStringToInt(InsertText.Text, out int index, 0, Gumps.GetCount()))
+            if (!Utils.ConvertStringToInt(InsertText.Text, out int index, 0, Gumps.GetCount() - 1))
             {
                 return;
             }
@@ -848,9 +851,9 @@ private void OnKeydown_InsertText(object sender, KeyEventArgs e)
                 {
                     Bitmap bitmap = new Bitmap(bmpTemp);
 
-                    if (dialog.FileName.Contains(".bmp"))
+                    if (dialog.FileName.EndsWith(".bmp", StringComparison.OrdinalIgnoreCase))
                     {
-                        bitmap = Utils.ConvertBmp(bitmap);
+                        bitmap = Utils.ConvertBmpAndDispose(bitmap);
                     }
 
                     Gumps.ReplaceGump(index, bitmap);
@@ -1160,9 +1163,9 @@ private void AddSingleGump(string fileName, int index)
             {
                 Bitmap bitmap = new Bitmap(bmpTemp);
 
-                if (fileName.Contains(".bmp"))
+                if (fileName.EndsWith(".bmp", StringComparison.OrdinalIgnoreCase))
                 {
-                    bitmap = Utils.ConvertBmp(bitmap);
+                    bitmap = Utils.ConvertBmpAndDispose(bitmap);
                 }
 
                 Gumps.ReplaceGump(index, bitmap);
diff --git a/UoFiddler.Controls/UserControls/HuesControl.cs b/UoFiddler.Controls/UserControls/HuesControl.cs
index 6687cf25..c1a25e33 100644
--- a/UoFiddler.Controls/UserControls/HuesControl.cs
+++ b/UoFiddler.Controls/UserControls/HuesControl.cs
@@ -259,13 +259,23 @@ private void OnKeyDownReplace(object sender, KeyEventArgs e)
                 return;
             }
 
-            if (!Utils.ConvertStringToInt(ReplaceText.Text, out int index, 0, Hues.List.Length))
+            if (!Utils.ConvertStringToInt(ReplaceText.Text, out int index, 0, Hues.List.Length - 1))
             {
                 return;
             }
 
             contextMenuStrip1.Close();
-            Hues.List[_selected] = Hues.List[index];
+
+            // Copy the values: sharing the source Hue object would tie both slots together.
+            Hue source = Hues.List[index];
+            Hue target = Hues.List[_selected];
+            source.Colors.CopyTo(target.Colors, 0);
+            target.Name = source.Name;
+            target.TableStart = source.TableStart;
+            target.TableEnd = source.TableEnd;
+
+            ControlEvents.FireHueChangeEvent();
+            Options.ChangedUltimaClass["Hues"] = true;
             pictureBox.Invalidate();
         }
 
diff --git a/UoFiddler.Controls/UserControls/ItemsControl.cs b/UoFiddler.Controls/UserControls/ItemsControl.cs
index 4b1446fe..8d2eea93 100644
--- a/UoFiddler.Controls/UserControls/ItemsControl.cs
+++ b/UoFiddler.Controls/UserControls/ItemsControl.cs
@@ -623,9 +623,9 @@ private void OnClickReplace(object sender, EventArgs e)
                 {
                     Bitmap bitmap = new Bitmap(bmpTemp);
 
-                    if (dialog.FileName.Contains(".bmp"))
+                    if (dialog.FileName.EndsWith(".bmp", StringComparison.OrdinalIgnoreCase))
                     {
-                        bitmap = Utils.ConvertBmp(bitmap);
+                        bitmap = Utils.ConvertBmpAndDispose(bitmap);
                     }
 
                     // Validate image size before replacing
@@ -700,9 +700,9 @@ private void ReplaceMultipleSelected()
                         {
                             Bitmap bitmap = new Bitmap(bmpTemp);
 
-                            if (files[i].Contains(".bmp"))
+                            if (files[i].EndsWith(".bmp", StringComparison.OrdinalIgnoreCase))
                             {
-                                bitmap = Utils.ConvertBmp(bitmap);
+                                bitmap = Utils.ConvertBmpAndDispose(bitmap);
                             }
 
                             if (!Art.ValidateStaticSize(bitmap, out int estimatedSize))
@@ -834,7 +834,14 @@ private void OnKeyDownInsertText(object sender, KeyEventArgs e)
                     return;
                 }
 
-                AddSingleItem(dialog.FileName, index);
+                try
+                {
+                    AddSingleItem(dialog.FileName, index);
+                }
+                catch (ArgumentException ex)
+                {
+                    MessageBox.Show($"{Path.GetFileName(dialog.FileName)}: {ex.Message}\n\nNo changes made.", "Insert", MessageBoxButtons.OK, MessageBoxIcon.Warning);
+                }
             }
         }
 
@@ -1382,16 +1389,19 @@ private void OnClickPreLoad(object sender, EventArgs e)
             ProgressBar.Step = 1;
             ProgressBar.Value = 1;
             ProgressBar.Visible = true;
-            PreLoader.RunWorkerAsync();
+
+            // The worker gets its own copy: the list can change while it runs.
+            PreLoader.RunWorkerAsync(_itemList.ToArray());
         }
 
         private void PreLoaderDoWork(object sender, DoWorkEventArgs e)
         {
-            int total = _itemList.Count;
+            var items = (int[])e.Argument;
+            int total = items.Length;
             int reportEvery = Math.Max(1, total / 200);
             int sinceReport = 0;
             int done = 0;
-            foreach (int item in _itemList)
+            foreach (int item in items)
             {
                 Art.GetStatic(item);
                 ++done;
@@ -1412,6 +1422,11 @@ private void PreLoaderProgressChanged(object sender, ProgressChangedEventArgs e)
         private void PreLoaderCompleted(object sender, RunWorkerCompletedEventArgs e)
         {
             ProgressBar.Visible = false;
+
+            if (e.Error != null)
+            {
+                MessageBox.Show($"Preloading items stopped: {e.Error.Message}", "Preload", MessageBoxButtons.OK, MessageBoxIcon.Warning);
+            }
         }
 
         private void ItemsTileView_DrawItem(object sender, TileViewControl.DrawTileListItemEventArgs e)
@@ -1531,7 +1546,7 @@ private void UpdateSelection(int itemIndex)
                 return;
             }
 
-            SelectedGraphicId = itemIndex < 0 || itemIndex > _itemList.Count
+            SelectedGraphicId = itemIndex < 0 || itemIndex >= _itemList.Count
                 ? _itemList[0]
                 : _itemList[itemIndex];
         }
@@ -1675,16 +1690,29 @@ private void ReplaceStartingFromText_KeyDown(object sender, KeyEventArgs e)
                     return;
                 }
 
+                var failed = new List<string>();
                 for (int i = 0; i < dialog.FileNames.Length; i++)
                 {
                     var currentIdx = index + i;
 
                     if (IsIndexValid(currentIdx))
                     {
-                        AddSingleItem(dialog.FileNames[i], currentIdx);
+                        try
+                        {
+                            AddSingleItem(dialog.FileNames[i], currentIdx);
+                        }
+                        catch (ArgumentException ex)
+                        {
+                            failed.Add($"0x{currentIdx:X4} {Path.GetFileName(dialog.FileNames[i])}: {ex.Message}");
+                        }
                     }
                 }
 
+                if (failed.Count > 0)
+                {
+                    MessageBox.Show($"Skipped {failed.Count} file(s):\n\n{string.Join("\n", failed)}", "Replace", MessageBoxButtons.OK, MessageBoxIcon.Warning);
+                }
+
                 ItemsTileView.VirtualListSize = _itemList.Count;
                 ItemsTileView.Invalidate();
 
@@ -1700,15 +1728,24 @@ private void ReplaceStartingFromText_KeyDown(object sender, KeyEventArgs e)
         /// </summary>
         /// <param name="fileName">Filename of the image to add.</param>
         /// <param name="index">Index where the static item will be added.</param>
+        /// <exception cref="ArgumentException">Thrown when the image is too large for the MUL format</exception>
         private void AddSingleItem(string fileName, int index)
         {
             using (var bmpTemp = new Bitmap(fileName))
             {
                 Bitmap bitmap = new Bitmap(bmpTemp);
 
-                if (fileName.Contains(".bmp"))
+                if (fileName.EndsWith(".bmp", StringComparison.OrdinalIgnoreCase))
                 {
-                    bitmap = Utils.ConvertBmp(bitmap);
+                    bitmap = Utils.ConvertBmpAndDispose(bitmap);
+                }
+
+                // Checked before anything changes, so a failed file leaves the list as it was.
+                if (!Art.ValidateStaticSize(bitmap, out int estimatedSize))
+                {
+                    string size = $"{bitmap.Width}x{bitmap.Height}";
+                    bitmap.Dispose();
+                    throw new ArgumentException($"image too large: {size}, {estimatedSize:N0} of 65,535 ushorts");
                 }
 
                 Art.ReplaceStatic(index, bitmap);
@@ -1823,6 +1860,10 @@ private void OnClickReplaceFromFolder(object sender, EventArgs e)
                     AddSingleItem(file, index);
                     replacedLines.Add($"  0x{index:X4}  {name}");
                 }
+                catch (ArgumentException ex)
+                {
+                    skippedLines.Add($"  {name}  ({ex.Message})");
+                }
                 catch
                 {
                     skippedLines.Add($"  {name}  (failed to load image)");
diff --git a/UoFiddler.Controls/UserControls/LandTilesControl.cs b/UoFiddler.Controls/UserControls/LandTilesControl.cs
index 0e11bfb9..c738c5e8 100644
--- a/UoFiddler.Controls/UserControls/LandTilesControl.cs
+++ b/UoFiddler.Controls/UserControls/LandTilesControl.cs
@@ -178,11 +178,18 @@ private void OnLoad(object sender, EventArgs e)
                 return;
             }
 
+            // A cross-tab Select loads the tab before its own Load event fires.
+            if (IsLoaded && (!(e is MyEventArgs args) || args.Type != MyEventArgs.Types.ForceReload))
+            {
+                return;
+            }
+
             using (new WaitCursorScope(this))
             {
                 Options.LoadedUltimaClass["TileData"] = true;
                 Options.LoadedUltimaClass["Art"] = true;
 
+                _tileList.Clear();
                 _showFreeSlots = false;
                 showFreeSlotsToolStripMenuItem.Checked = false;
 
@@ -501,23 +508,14 @@ private void OnClickReplace(object sender, EventArgs e)
                 {
                     Bitmap bitmap = new Bitmap(bmpTemp);
 
-                    if (dialog.FileName.Contains(".bmp"))
+                    if (dialog.FileName.EndsWith(".bmp", StringComparison.OrdinalIgnoreCase))
                     {
-                        bitmap = Utils.ConvertBmp(bitmap);
+                        bitmap = Utils.ConvertBmpAndDispose(bitmap);
                     }
 
-                    // Validate image size (land tiles should be 44x44 but check anyway)
-                    if (!Art.ValidateStaticSize(bitmap, out int estimatedSize))
+                    if (!CheckLandTileSize(bitmap, Path.GetFileName(dialog.FileName)))
                     {
-                        MessageBox.Show(
-                            $"Image is too large for MUL format!\n\n" +
-                            $"Image dimensions: {bitmap.Width}x{bitmap.Height}\n" +
-                            $"Estimated encoded size: {estimatedSize:N0} ushorts\n" +
-                            $"Maximum allowed: 65,535 ushorts\n\n" +
-                            $"Note: Land tiles should typically be 44x44 pixels.",
-                            "Image Too Large",
-                            MessageBoxButtons.OK,
-                            MessageBoxIcon.Warning);
+                        bitmap.Dispose();
                         return;
                     }
 
@@ -574,24 +572,19 @@ private void ReplaceMultipleSelected()
                         {
                             Bitmap bitmap = new Bitmap(bmpTemp);
 
-                            if (files[i].Contains(".bmp"))
+                            if (files[i].EndsWith(".bmp", StringComparison.OrdinalIgnoreCase))
                             {
-                                bitmap = Utils.ConvertBmp(bitmap);
+                                bitmap = Utils.ConvertBmpAndDispose(bitmap);
                             }
 
-                            if (!Art.ValidateStaticSize(bitmap, out int estimatedSize))
+                            if (!CheckLandTileSize(bitmap, Path.GetFileName(files[i])))
                             {
                                 bitmap.Dispose();
-                                MessageBox.Show(
-                                    $"Image is too large for MUL format!\n\n" +
-                                    $"File: {Path.GetFileName(files[i])}\n" +
-                                    $"Estimated encoded size: {estimatedSize:N0} ushorts\n" +
-                                    $"Maximum allowed: 65,535 ushorts\n\n" +
-                                    $"Note: Land tiles should typically be 44x44 pixels.\n" +
-                                    $"No changes made.",
-                                    "Image Too Large",
-                                    MessageBoxButtons.OK,
-                                    MessageBoxIcon.Warning);
+                                foreach (var loaded in bitmaps)
+                                {
+                                    loaded.Dispose();
+                                }
+
                                 return;
                             }
 
@@ -672,15 +665,23 @@ private void OnKeyDownInsert(object sender, KeyEventArgs e)
                 {
                     Bitmap bitmap = new Bitmap(bmpTemp);
 
-                    if (dialog.FileName.Contains(".bmp"))
+                    if (dialog.FileName.EndsWith(".bmp", StringComparison.OrdinalIgnoreCase))
+                    {
+                        bitmap = Utils.ConvertBmpAndDispose(bitmap);
+                    }
+
+                    if (!CheckLandTileSize(bitmap, Path.GetFileName(dialog.FileName)))
                     {
-                        bitmap = Utils.ConvertBmp(bitmap);
+                        bitmap.Dispose();
+                        return;
                     }
 
                     Art.ReplaceLand(index, bitmap);
 
                     ControlEvents.FireLandTileChangeEvent(this, index);
 
+                    Options.ChangedUltimaClass["Art"] = true;
+
                     if (_showFreeSlots)
                     {
                         SelectedGraphicId = index;
@@ -709,8 +710,6 @@ private void OnKeyDownInsert(object sender, KeyEventArgs e)
                         LandTilesTileView.VirtualListSize = _tileList.Count;
                         LandTilesTileView.Invalidate();
                         SelectedGraphicId = index;
-
-                        Options.ChangedUltimaClass["Art"] = true;
                     }
                 }
             }
@@ -1017,7 +1016,7 @@ private void LandTilesTileView_ItemSelectionChanged(object sender, ListViewItemS
                 return;
             }
 
-            SelectedGraphicId = e.ItemIndex < 0 || e.ItemIndex > _tileList.Count
+            SelectedGraphicId = e.ItemIndex < 0 || e.ItemIndex >= _tileList.Count
                 ? _tileList[0]
                 : _tileList[e.ItemIndex];
         }
@@ -1130,6 +1129,10 @@ private void OnClickReplaceFromFolder(object sender, EventArgs e)
                     AddSingleLandTile(file, index);
                     replacedLines.Add($"  0x{index:X4}  {name}");
                 }
+                catch (ArgumentException ex)
+                {
+                    skippedLines.Add($"  {name}  ({ex.Message})");
+                }
                 catch
                 {
                     skippedLines.Add($"  {name}  (failed to load image)");
@@ -1182,9 +1185,16 @@ private void AddSingleLandTile(string fileName, int index)
             {
                 Bitmap bitmap = new Bitmap(bmpTemp);
 
-                if (fileName.Contains(".bmp"))
+                if (fileName.EndsWith(".bmp", StringComparison.OrdinalIgnoreCase))
                 {
-                    bitmap = Utils.ConvertBmp(bitmap);
+                    bitmap = Utils.ConvertBmpAndDispose(bitmap);
+                }
+
+                if (bitmap.Width != LandTileSize || bitmap.Height != LandTileSize)
+                {
+                    string size = $"{bitmap.Width}x{bitmap.Height}";
+                    bitmap.Dispose();
+                    throw new ArgumentException($"{size}, land tiles must be {LandTileSize}x{LandTileSize}");
                 }
 
                 Art.ReplaceLand(index, bitmap);
@@ -1200,7 +1210,12 @@ private void AddSingleLandTile(string fileName, int index)
                         continue;
                     }
 
-                    _tileList[i] = index;
+                    // Insert before the first larger id; the id may already be listed
+                    if (_tileList[i] != index)
+                    {
+                        _tileList.Insert(i, index);
+                    }
+
                     done = true;
                     break;
                 }
@@ -1212,6 +1227,25 @@ private void AddSingleLandTile(string fileName, int index)
             }
         }
 
+        /// <summary>
+        /// Land art is a fixed 44x44 block; anything else would be written out as garbage.
+        /// </summary>
+        private bool CheckLandTileSize(Bitmap bitmap, string source)
+        {
+            if (bitmap.Width == LandTileSize && bitmap.Height == LandTileSize)
+            {
+                return true;
+            }
+
+            MessageBox.Show(
+                $"Invalid land tile dimensions!\n\n" +
+                $"{source}: {bitmap.Width}x{bitmap.Height}\n" +
+                $"Land tiles must be {LandTileSize}x{LandTileSize} pixels.\n\n" +
+                "No changes made.",
+                "Invalid Size", MessageBoxButtons.OK, MessageBoxIcon.Warning);
+            return false;
+        }
+
         public void UpdateTileView()
         {
             LandTilesTileView.TileBorderColor = Options.RemoveTileBorder
diff --git a/UoFiddler.Controls/UserControls/LightControl.cs b/UoFiddler.Controls/UserControls/LightControl.cs
index 3045f734..90ced436 100644
--- a/UoFiddler.Controls/UserControls/LightControl.cs
+++ b/UoFiddler.Controls/UserControls/LightControl.cs
@@ -156,7 +156,7 @@ private unsafe Bitmap GetImage()
             int lightStartY = 30 + (bit.Height / 2) - (lightHeight / 2);
 
             int lightEndX = lightStartX + lightWidth;
-            int lightEndY = lightStartY + lightWidth;
+            int lightEndY = lightStartY + lightHeight;
 
             for (int y = 0; y < bd.Height; ++y)
             {
@@ -170,7 +170,8 @@ private unsafe Bitmap GetImage()
 
                     if (x >= lightStartX && x < lightEndX && y >= lightStartY && y < lightEndY)
                     {
-                        int offset = ((y - lightStartY) * lightHeight) + (x - lightStartX);
+                        // Light data is stored row by row, lightWidth bytes per row.
+                        int offset = ((y - lightStartY) * lightWidth) + (x - lightStartX);
                         if (offset < light.Length)
                         {
                             lightC = light[offset];
@@ -187,9 +188,9 @@ private unsafe Bitmap GetImage()
                     r /= 3;
                     g /= 3;
                     b /= 3;
-                    r += (byte)(r * lightC);
-                    g += (byte)(g * lightC);
-                    b += (byte)(b * lightC);
+                    r = (byte)Math.Min(255, r + (r * lightC));
+                    g = (byte)Math.Min(255, g + (g * lightC));
+                    b = (byte)Math.Min(255, b + (b * lightC));
 
                     *imgPtr++ = b;
                     *imgPtr++ = g;
@@ -251,9 +252,9 @@ private void OnClickReplace(object sender, EventArgs e)
                 {
                     var bitmap = new Bitmap(bmpTemp);
 
-                    if (dialog.FileName.Contains(".bmp"))
+                    if (dialog.FileName.EndsWith(".bmp", StringComparison.OrdinalIgnoreCase))
                     {
-                        bitmap = Utils.ConvertBmp(bitmap);
+                        bitmap = Utils.ConvertBmpAndDispose(bitmap);
                     }
 
                     int i = (int)listViewLights.SelectedItems[0].Tag;
diff --git a/UoFiddler.Controls/UserControls/MultisControl.cs b/UoFiddler.Controls/UserControls/MultisControl.cs
index 8ca277cc..714957c3 100644
--- a/UoFiddler.Controls/UserControls/MultisControl.cs
+++ b/UoFiddler.Controls/UserControls/MultisControl.cs
@@ -349,7 +349,7 @@ public void ChangeMulti(int id, MultiComponentList multi)
 
             _refMarker.SelectMulRow(pos);
             _refMarker.AfterSelect_Multi(this, EventArgs.Empty);
-            ControlEvents.FireMultiChangeEvent(this, pos);
+            ControlEvents.FireMultiChangeEvent(this, id);
         }
 
         private void AfterSelect_Multi(object sender, EventArgs e)
diff --git a/UoFiddler.Controls/UserControls/SoundsControl.cs b/UoFiddler.Controls/UserControls/SoundsControl.cs
index 47555dc5..77d0d8c8 100644
--- a/UoFiddler.Controls/UserControls/SoundsControl.cs
+++ b/UoFiddler.Controls/UserControls/SoundsControl.cs
@@ -553,6 +553,7 @@ private void OnClickReplace(object sender, EventArgs e)
             if (!File.Exists(file))
             {
                 MessageBox.Show("Invalid Filename", "Add/Replace", MessageBoxButtons.OK, MessageBoxIcon.Error, MessageBoxDefaultButton.Button1);
+                return;
             }
 
             if (name.Length > 32)
diff --git a/UoFiddler.Controls/UserControls/TexturesControl.cs b/UoFiddler.Controls/UserControls/TexturesControl.cs
index 20bfd309..05eadb0d 100644
--- a/UoFiddler.Controls/UserControls/TexturesControl.cs
+++ b/UoFiddler.Controls/UserControls/TexturesControl.cs
@@ -104,7 +104,7 @@ private void Reload()
 
             _selectedTextureId = -1;
 
-            OnLoad(this, EventArgs.Empty);
+            OnLoad(this, new MyEventArgs(MyEventArgs.Types.ForceReload));
         }
 
         private void OnLoad(object sender, EventArgs e)
@@ -114,10 +114,18 @@ private void OnLoad(object sender, EventArgs e)
                 return;
             }
 
+            // A cross-tab Select loads the tab before its own Load event fires.
+            if (_loaded && (!(e is MyEventArgs args) || args.Type != MyEventArgs.Types.ForceReload))
+            {
+                return;
+            }
+
             using (new WaitCursorScope(this))
             {
                 Options.LoadedUltimaClass["Texture"] = true;
 
+                _textureList.Clear();
+
                 for (int i = 0; i < Textures.GetIdxLength(); ++i)
                 {
                     if (Textures.TestTexture(i))
@@ -402,11 +410,22 @@ private void OnClickReplace(object sender, EventArgs e)
 
                 using (var bmpTemp = new Bitmap(dialog.FileName))
                 {
+                    if (!IsValidTextureSize(bmpTemp))
+                    {
+                        MessageBox.Show(
+                            $"Invalid texture dimensions!\n\n" +
+                            $"File: {Path.GetFileName(dialog.FileName)} ({bmpTemp.Width}x{bmpTemp.Height})\n" +
+                            $"Textures must be 64x64 or 128x128 pixels.\n\n" +
+                            "No changes made.",
+                            "Invalid Size", MessageBoxButtons.OK, MessageBoxIcon.Warning);
+                        return;
+                    }
+
                     Bitmap bitmap = new Bitmap(bmpTemp);
 
-                    if (dialog.FileName.Contains(".bmp"))
+                    if (dialog.FileName.EndsWith(".bmp", StringComparison.OrdinalIgnoreCase))
                     {
-                        bitmap = Utils.ConvertBmp(bitmap);
+                        bitmap = Utils.ConvertBmpAndDispose(bitmap);
                     }
 
                     Textures.Replace(_selectedTextureId, bitmap);
@@ -478,9 +497,9 @@ private void ReplaceMultipleSelected()
 
                             Bitmap bitmap = new Bitmap(bmpTemp);
 
-                            if (files[i].Contains(".bmp"))
+                            if (files[i].EndsWith(".bmp", StringComparison.OrdinalIgnoreCase))
                             {
-                                bitmap = Utils.ConvertBmp(bitmap);
+                                bitmap = Utils.ConvertBmpAndDispose(bitmap);
                             }
 
                             bitmaps.Add(bitmap);
@@ -557,9 +576,9 @@ private void OnKeyDownInsert(object sender, KeyEventArgs e)
                     {
                         Bitmap bitmap = new Bitmap(bmpTemp);
 
-                        if (dialog.FileName.Contains(".bmp"))
+                        if (dialog.FileName.EndsWith(".bmp", StringComparison.OrdinalIgnoreCase))
                         {
-                            bitmap = Utils.ConvertBmp(bitmap);
+                            bitmap = Utils.ConvertBmpAndDispose(bitmap);
                         }
 
                         Textures.Replace(index, bitmap);
@@ -719,7 +738,7 @@ private void TextureTileView_ItemSelectionChanged(object sender, ListViewItemSel
                 return;
             }
 
-            SelectedTextureId = e.ItemIndex < 0 || e.ItemIndex > _textureList.Count
+            SelectedTextureId = e.ItemIndex < 0 || e.ItemIndex >= _textureList.Count
                 ? _textureList[0]
                 : _textureList[e.ItemIndex];
         }
@@ -918,9 +937,9 @@ private void AddSingleTexture(string fileName, int index)
                 {
                     Bitmap bitmap = new Bitmap(bmpTemp);
 
-                    if (fileName.Contains(".bmp"))
+                    if (fileName.EndsWith(".bmp", StringComparison.OrdinalIgnoreCase))
                     {
-                        bitmap = Utils.ConvertBmp(bitmap);
+                        bitmap = Utils.ConvertBmpAndDispose(bitmap);
                     }
 
                     Textures.Replace(index, bitmap);
diff --git a/UoFiddler.Plugin.ExamplePlugin/ExamplePluginBase.cs b/UoFiddler.Plugin.ExamplePlugin/ExamplePluginBase.cs
index 5ecd39b7..0d539fc2 100644
--- a/UoFiddler.Plugin.ExamplePlugin/ExamplePluginBase.cs
+++ b/UoFiddler.Plugin.ExamplePlugin/ExamplePluginBase.cs
@@ -27,11 +27,6 @@ public class ExamplePluginBase : PluginBase
     {
         private const string _itemDescFileName = "itemdesc.cfg";
 
-        public ExamplePluginBase()
-        {
-            PluginEvents.ModifyItemsControlContextMenuEvent += EventsModifyItemsControlContextMenuEvent;
-        }
-
         /// <summary>
         /// Name of the plugin
         /// </summary>
@@ -61,10 +56,14 @@ public override void Initialize()
         {
             // make something useful
             _ = Files.RootDir;
+
+            // Subscribe here, not in the constructor: the Manage Plugins form constructs disabled plugins too.
+            PluginEvents.ModifyItemsControlContextMenuEvent += EventsModifyItemsControlContextMenuEvent;
         }
 
         public override void Unload()
         {
+            PluginEvents.ModifyItemsControlContextMenuEvent -= EventsModifyItemsControlContextMenuEvent;
         }
 
         public override void ModifyTabPages(TabControl tabControl)
diff --git a/UoFiddler.Plugin.MassImport/Forms/MassImportForm.cs b/UoFiddler.Plugin.MassImport/Forms/MassImportForm.cs
index 4176accf..e84c1626 100644
--- a/UoFiddler.Plugin.MassImport/Forms/MassImportForm.cs
+++ b/UoFiddler.Plugin.MassImport/Forms/MassImportForm.cs
@@ -174,6 +174,9 @@ private void LoadXMLOnClick(object sender, EventArgs e)
 
             int currBoxLength = 0;
 
+            // Relative file paths are relative to the XML file, not to the working directory.
+            string baseDirectory = Path.GetDirectoryName(Path.GetFullPath(fileName));
+
             foreach (XmlNode xNode in dom.SelectSingleNode("MassImport"))
             {
                 if (xNode.NodeType == XmlNodeType.Comment)
@@ -213,13 +216,14 @@ private void LoadXMLOnClick(object sender, EventArgs e)
                         break;
                 }
 
-                entry.File = xNode.Attributes["file"].InnerText;
+                // A missing attribute reads as empty: no file, an invalid index, or not a removal.
+                entry.File = xNode.Attributes?["file"]?.InnerText ?? string.Empty;
                 if (!string.IsNullOrEmpty(entry.File))
                 {
-                    entry.File = Path.GetFullPath(entry.File);
+                    entry.File = Path.GetFullPath(entry.File, baseDirectory);
                 }
 
-                if (Utils.ConvertStringToInt(xNode.Attributes["index"].InnerText, out int temp))
+                if (Utils.ConvertStringToInt(xNode.Attributes?["index"]?.InnerText ?? string.Empty, out int temp))
                 {
                     entry.Index = temp;
                 }
@@ -228,7 +232,7 @@ private void LoadXMLOnClick(object sender, EventArgs e)
                     entry.Index = -1;
                 }
 
-                entry.Remove = bool.Parse(xNode.Attributes["remove"].InnerText);
+                entry.Remove = bool.TryParse(xNode.Attributes?["remove"]?.InnerText, out bool remove) && remove;
                 entry.Valid = true;
 
                 string message = entry.Test();
diff --git a/UoFiddler.Plugin.MassImport/Imports/ImportEntry.cs b/UoFiddler.Plugin.MassImport/Imports/ImportEntry.cs
index ed2d95e2..e01772f4 100644
--- a/UoFiddler.Plugin.MassImport/Imports/ImportEntry.cs
+++ b/UoFiddler.Plugin.MassImport/Imports/ImportEntry.cs
@@ -33,7 +33,7 @@ public abstract class ImportEntry
 
         protected virtual void TestFile(ref string message)
         {
-            if (File.Contains(".bmp") || File.Contains(".tiff") || File.Contains(".png") || File.Contains(".jpg") || File.Contains(".jpeg"))
+            if (File.EndsWith(".bmp", System.StringComparison.OrdinalIgnoreCase) || File.EndsWith(".tiff", System.StringComparison.OrdinalIgnoreCase) || File.EndsWith(".png", System.StringComparison.OrdinalIgnoreCase) || File.EndsWith(".jpg", System.StringComparison.OrdinalIgnoreCase) || File.EndsWith(".jpeg", System.StringComparison.OrdinalIgnoreCase))
             {
                 return;
             }
diff --git a/UoFiddler.Plugin.MassImport/Imports/ImportEntryGump.cs b/UoFiddler.Plugin.MassImport/Imports/ImportEntryGump.cs
index cfcb65c7..ae376e78 100644
--- a/UoFiddler.Plugin.MassImport/Imports/ImportEntryGump.cs
+++ b/UoFiddler.Plugin.MassImport/Imports/ImportEntryGump.cs
@@ -29,9 +29,9 @@ public override void Import(bool direct, ref Dictionary<string, bool> changedCla
                 {
                     Bitmap bitmap = new Bitmap(bmpTemp);
 
-                    if (File.Contains(".bmp"))
+                    if (File.EndsWith(".bmp", System.StringComparison.OrdinalIgnoreCase))
                     {
-                        bitmap = Utils.ConvertBmp(bitmap);
+                        bitmap = Utils.ConvertBmpAndDispose(bitmap);
                     }
 
                     Ultima.Gumps.ReplaceGump(Index, bitmap);
diff --git a/UoFiddler.Plugin.MassImport/Imports/ImportEntryHue.cs b/UoFiddler.Plugin.MassImport/Imports/ImportEntryHue.cs
index 2195a7ed..9d8f261a 100644
--- a/UoFiddler.Plugin.MassImport/Imports/ImportEntryHue.cs
+++ b/UoFiddler.Plugin.MassImport/Imports/ImportEntryHue.cs
@@ -16,13 +16,13 @@ namespace UoFiddler.Plugin.MassImport.Imports
 {
     public class ImportEntryHue : ImportEntry
     {
-        public override int MaxIndex => 3000;
+        public override int MaxIndex => Ultima.Hues.List.Length - 1;
 
         public override string Name => "Hue";
 
         protected override void TestFile(ref string message)
         {
-            if (!File.Contains(".txt"))
+            if (!File.EndsWith(".txt", System.StringComparison.OrdinalIgnoreCase))
             {
                 message += " Invalid file format";
                 Valid = false;
diff --git a/UoFiddler.Plugin.MassImport/Imports/ImportEntryItem.cs b/UoFiddler.Plugin.MassImport/Imports/ImportEntryItem.cs
index c6d883dc..0ac7027a 100644
--- a/UoFiddler.Plugin.MassImport/Imports/ImportEntryItem.cs
+++ b/UoFiddler.Plugin.MassImport/Imports/ImportEntryItem.cs
@@ -29,9 +29,9 @@ public override void Import(bool direct, ref Dictionary<string, bool> changedCla
                 {
                     Bitmap bitmap = new Bitmap(bmpTemp);
 
-                    if (File.Contains(".bmp"))
+                    if (File.EndsWith(".bmp", System.StringComparison.OrdinalIgnoreCase))
                     {
-                        bitmap = Utils.ConvertBmp(bitmap);
+                        bitmap = Utils.ConvertBmpAndDispose(bitmap);
                     }
 
                     Ultima.Art.ReplaceStatic(Index, bitmap);
diff --git a/UoFiddler.Plugin.MassImport/Imports/ImportEntryLandTile.cs b/UoFiddler.Plugin.MassImport/Imports/ImportEntryLandTile.cs
index cc916e15..e420b6fa 100644
--- a/UoFiddler.Plugin.MassImport/Imports/ImportEntryLandTile.cs
+++ b/UoFiddler.Plugin.MassImport/Imports/ImportEntryLandTile.cs
@@ -27,9 +27,9 @@ public override void Import(bool direct, ref Dictionary<string, bool> changedCla
                 {
                     Bitmap bitmap = new Bitmap(bmpTemp);
 
-                    if (File.Contains(".bmp"))
+                    if (File.EndsWith(".bmp", System.StringComparison.OrdinalIgnoreCase))
                     {
-                        bitmap = Utils.ConvertBmp(bitmap);
+                        bitmap = Utils.ConvertBmpAndDispose(bitmap);
                     }
 
                     Ultima.Art.ReplaceLand(Index, bitmap);
diff --git a/UoFiddler.Plugin.MassImport/Imports/ImportEntryMulti.cs b/UoFiddler.Plugin.MassImport/Imports/ImportEntryMulti.cs
index 30376072..711b9ad1 100644
--- a/UoFiddler.Plugin.MassImport/Imports/ImportEntryMulti.cs
+++ b/UoFiddler.Plugin.MassImport/Imports/ImportEntryMulti.cs
@@ -19,7 +19,7 @@ namespace UoFiddler.Plugin.MassImport.Imports
 {
     internal class ImportEntryMulti : ImportEntry
     {
-        public override int MaxIndex => Multis.MaximumMultiIndex;
+        public override int MaxIndex => Multis.MaximumMultiIndex - 1;
 
         public override string Name => "Multi";
 
diff --git a/UoFiddler.Plugin.MassImport/Imports/ImportEntryTexture.cs b/UoFiddler.Plugin.MassImport/Imports/ImportEntryTexture.cs
index ba4792c3..2e3a9c3e 100644
--- a/UoFiddler.Plugin.MassImport/Imports/ImportEntryTexture.cs
+++ b/UoFiddler.Plugin.MassImport/Imports/ImportEntryTexture.cs
@@ -17,7 +17,7 @@ namespace UoFiddler.Plugin.MassImport.Imports
 {
     public class ImportEntryTexture : ImportEntry
     {
-        public override int MaxIndex => Ultima.Textures.GetIdxLength();
+        public override int MaxIndex => Ultima.Textures.GetIdxLength() - 1;
 
         public override string Name => "Texture";
 
@@ -29,9 +29,9 @@ public override void Import(bool direct, ref Dictionary<string, bool> changedCla
                 {
                     Bitmap bitmap = new Bitmap(bmpTemp);
 
-                    if (File.Contains(".bmp"))
+                    if (File.EndsWith(".bmp", System.StringComparison.OrdinalIgnoreCase))
                     {
-                        bitmap = Utils.ConvertBmp(bitmap);
+                        bitmap = Utils.ConvertBmpAndDispose(bitmap);
                     }
 
                     Ultima.Textures.Replace(Index, bitmap);
diff --git a/UoFiddler.Plugin.MassImport/Imports/ImportEntryTileDataItem.cs b/UoFiddler.Plugin.MassImport/Imports/ImportEntryTileDataItem.cs
index 2c3a3c6b..a85e3a7f 100644
--- a/UoFiddler.Plugin.MassImport/Imports/ImportEntryTileDataItem.cs
+++ b/UoFiddler.Plugin.MassImport/Imports/ImportEntryTileDataItem.cs
@@ -28,7 +28,7 @@ public class ImportEntryTileDataItem : ImportEntry
 
         protected override void TestFile(ref string message)
         {
-            if (!File.Contains(".csv"))
+            if (!File.EndsWith(".csv", System.StringComparison.OrdinalIgnoreCase))
             {
                 message += " Invalid File format";
                 Valid = false;
diff --git a/UoFiddler.Plugin.MassImport/Imports/ImportEntryTileDataLand.cs b/UoFiddler.Plugin.MassImport/Imports/ImportEntryTileDataLand.cs
index fff173fe..24434f98 100644
--- a/UoFiddler.Plugin.MassImport/Imports/ImportEntryTileDataLand.cs
+++ b/UoFiddler.Plugin.MassImport/Imports/ImportEntryTileDataLand.cs
@@ -26,7 +26,7 @@ public class ImportEntryTileDataLand : ImportEntry
 
         protected override void TestFile(ref string message)
         {
-            if (!File.Contains(".csv"))
+            if (!File.EndsWith(".csv", System.StringComparison.OrdinalIgnoreCase))
             {
                 message += " Invalid file format";
                 Valid = false;
diff --git a/UoFiddler.Plugin.MultiEditor/Classes/MultiEditorComponentList.cs b/UoFiddler.Plugin.MultiEditor/Classes/MultiEditorComponentList.cs
index d197324a..a7dcfde2 100644
--- a/UoFiddler.Plugin.MultiEditor/Classes/MultiEditorComponentList.cs
+++ b/UoFiddler.Plugin.MultiEditor/Classes/MultiEditorComponentList.cs
@@ -76,7 +76,10 @@ public MultiEditorComponentList(MultiComponentList list, MultiEditorControl pare
                             x,
                             y,
                             list.Tiles[x][y][i].Z,
-                            list.Tiles[x][y][i].Flag));
+                            list.Tiles[x][y][i].Flag)
+                        {
+                            Extra = list.Tiles[x][y][i].Unk1
+                        });
                     }
 
                     Tiles.Add(new FloorTile(x, y, _parent.DrawFloorZ));
@@ -150,7 +153,7 @@ public MultiComponentList ConvertToSdk()
                     continue;
                 }
 
-                tiles[tile.X][tile.Y].Add(tile.Id, (sbyte)tile.Z, tile.Invisible ? (sbyte)0 : (sbyte)1, 0);
+                tiles[tile.X][tile.Y].Add(tile.Id, (sbyte)tile.Z, tile.Invisible ? (sbyte)0 : (sbyte)1, tile.Extra);
                 ++count;
             }
 
@@ -398,7 +401,7 @@ public void TileAdd(int x, int y, int z, ushort id)
             }
 
             AddToUndoList("Add Tile");
-            MultiTile tile = new MultiTile(id, x, y, z, 1);
+            MultiTile tile = new MultiTile(id, x, y, ClampZ(z), 1);
             Tiles.Add(tile);
             CalcSolver(x, y);
             _modified = true;
@@ -406,6 +409,11 @@ public void TileAdd(int x, int y, int z, ushort id)
             RecalculateMinMax(tile);
         }
 
+        /// <summary>
+        /// Z is saved as a signed byte; larger values would wrap around.
+        /// </summary>
+        private static int ClampZ(int z) => Math.Clamp(z, sbyte.MinValue, sbyte.MaxValue);
+
         /// <summary>
         /// Moves given <see cref="MultiTile"/>
         /// </summary>
@@ -416,13 +424,14 @@ public void TileMove(MultiTile tile, int newX, int newY)
                 return;
             }
 
-            AddToUndoList("Move Tile");
-
-            if (tile == null)
+            // A tile from before an undo or another multi is no longer in the list.
+            if (tile == null || newX < 0 || newX >= Width || newY < 0 || newY >= Height || !Tiles.Contains(tile))
             {
                 return;
             }
 
+            AddToUndoList("Move Tile");
+
             tile.X = newX;
             tile.Y = newY;
             CalcSolver(newX, newY);
@@ -480,13 +489,13 @@ public void TileRemove(MultiTile tile)
                 return;
             }
 
-            AddToUndoList("Remove Tile");
-
-            if (tile == null)
+            if (tile == null || !Tiles.Contains(tile))
             {
                 return;
             }
 
+            AddToUndoList("Remove Tile");
+
             Tiles.Remove(tile);
             _modified = true;
             RecalculateMinMax(tile);
@@ -588,7 +597,7 @@ public void TileAddRect(int x0, int y0, int x1, int y1, int z, ushort id)
                         continue;
                     }
 
-                    Tiles.Add(new MultiTile(id, x, y, z, 1));
+                    Tiles.Add(new MultiTile(id, x, y, ClampZ(z), 1));
                     CalcSolver(x, y);
                 }
             }
@@ -611,7 +620,7 @@ public void TileAddLine(int x0, int y0, int x1, int y1, int z, ushort id)
                     continue;
                 }
 
-                Tiles.Add(new MultiTile(id, x, y, z, 1));
+                Tiles.Add(new MultiTile(id, x, y, ClampZ(z), 1));
                 CalcSolver(x, y);
             }
 
@@ -672,7 +681,7 @@ public void TileAddBrush(int cx, int cy, int z, ushort id, int brushSize)
                         continue;
                     }
 
-                    Tiles.Add(new MultiTile(id, x, y, z, 1));
+                    Tiles.Add(new MultiTile(id, x, y, ClampZ(z), 1));
                     CalcSolver(x, y);
                 }
             }
@@ -685,17 +694,17 @@ public void TileAddBrush(int cx, int cy, int z, ushort id, int brushSize)
         /// <summary>
         /// Adds a batch of tiles in a single undo step (used by copy/paste).
         /// </summary>
-        public void TileAddBatch(List<(ushort id, int x, int y, int z)> tiles)
+        public void TileAddBatch(List<(ushort id, int x, int y, int z, bool invisible, int extra)> tiles)
         {
             AddToUndoList("Paste");
-            foreach (var (id, x, y, z) in tiles)
+            foreach (var (id, x, y, z, invisible, extra) in tiles)
             {
                 if (x < 0 || x >= Width || y < 0 || y >= Height)
                 {
                     continue;
                 }
 
-                Tiles.Add(new MultiTile(id, x, y, z, 1));
+                Tiles.Add(new MultiTile(id, x, y, ClampZ(z), invisible) { Extra = extra });
                 CalcSolver(x, y);
             }
 
@@ -713,7 +722,7 @@ private void RestoreSnapshot(UndoStruct entry)
             {
                 Tiles.Add(tile.IsVirtualFloor
                     ? new FloorTile(tile.X, tile.Y, tile.Z)
-                    : new MultiTile(tile.Id, tile.X, tile.Y, tile.Z, tile.Invisible));
+                    : new MultiTile(tile.Id, tile.X, tile.Y, tile.Z, tile.Invisible) { Extra = tile.Extra });
             }
 
             _modified = true;
@@ -727,8 +736,27 @@ public void Undo(int index)
                 return;
             }
 
-            RestoreSnapshot(UndoList[index]);
-            RedoList.Clear();
+            // Step back one entry at a time, so every state passed over, the current one included,
+            // ends up on the redo stack and can be redone.
+            for (int i = 0; i <= index; ++i)
+            {
+                UndoStep();
+            }
+        }
+
+        /// <summary>
+        /// Sets a tile's Dynamic (invisible) flag as an undoable change.
+        /// </summary>
+        public void TileSetInvisible(MultiTile tile, bool invisible)
+        {
+            if (tile == null || tile.Invisible == invisible || !Tiles.Contains(tile))
+            {
+                return;
+            }
+
+            AddToUndoList("Dynamic");
+            tile.Invisible = invisible;
+            _modified = true;
         }
 
         /// <summary>Single-step undo (Ctrl+Z). Pushes current state to redo stack.</summary>
@@ -941,7 +969,7 @@ private UndoStruct SnapshotCurrent(string action)
             {
                 entry.Tiles.Add(tile.IsVirtualFloor
                     ? new FloorTile(tile.X, tile.Y, tile.Z)
-                    : new MultiTile(tile.Id, tile.X, tile.Y, tile.Z, tile.Invisible));
+                    : new MultiTile(tile.Id, tile.X, tile.Y, tile.Z, tile.Invisible) { Extra = tile.Extra });
             }
 
             return entry;
@@ -1341,6 +1369,11 @@ public int Z
 
         public bool Invisible { get; set; }
 
+        /// <summary>
+        /// The multi.mul extra field (MultiTileEntry.Unk1), kept so a save writes it back.
+        /// </summary>
+        public int Extra { get; set; }
+
         public bool Walkable { get; private set; }
 
         public bool DoubleSurface { get; private set; }
diff --git a/UoFiddler.Plugin.MultiEditor/MultiEditorPluginBase.cs b/UoFiddler.Plugin.MultiEditor/MultiEditorPluginBase.cs
index 90b55e5f..954b8e9d 100644
--- a/UoFiddler.Plugin.MultiEditor/MultiEditorPluginBase.cs
+++ b/UoFiddler.Plugin.MultiEditor/MultiEditorPluginBase.cs
@@ -21,11 +21,6 @@ public class MultiEditorPluginBase : PluginBase
     {
         private UserControls.MultiEditorControl _multiEditorControl;
 
-        public MultiEditorPluginBase()
-        {
-            PluginEvents.ModifyItemsControlContextMenuEvent += EventsModifyItemsControlContextMenuEvent;
-        }
-
         /// <summary>
         /// Author of the plugin
         /// </summary>
@@ -54,12 +49,15 @@ public MultiEditorPluginBase()
         public override void Unload()
         {
             // fired in Fiddler OnClosing
+            PluginEvents.ModifyItemsControlContextMenuEvent -= EventsModifyItemsControlContextMenuEvent;
         }
 
         public override void Initialize()
         {
-            // fired on fiddler startup
+            // fired on fiddler startup; the Manage Plugins form also constructs disabled plugins,
+            // so events are subscribed here and not in the constructor
             _ = Files.RootDir;
+            PluginEvents.ModifyItemsControlContextMenuEvent += EventsModifyItemsControlContextMenuEvent;
         }
 
         public override void ModifyPluginToolStrip(ToolStripDropDownButton toolStrip)
diff --git a/UoFiddler.Plugin.MultiEditor/UoFiddler.Plugin.MultiEditor.csproj b/UoFiddler.Plugin.MultiEditor/UoFiddler.Plugin.MultiEditor.csproj
index 3ddff6b9..544c5c33 100644
--- a/UoFiddler.Plugin.MultiEditor/UoFiddler.Plugin.MultiEditor.csproj
+++ b/UoFiddler.Plugin.MultiEditor/UoFiddler.Plugin.MultiEditor.csproj
@@ -7,8 +7,8 @@
 		<AssemblyTitle>MultiEditor</AssemblyTitle>
 		<Product>MultiEditor</Product>
 		<Copyright>Copyright © 2026</Copyright>
-		<AssemblyVersion>1.5.0.0</AssemblyVersion>
-		<FileVersion>1.5.0.0</FileVersion>
+		<AssemblyVersion>1.7.0.0</AssemblyVersion>
+		<FileVersion>1.7.0.0</FileVersion>
 		<GenerateResourceUsePreserializedResources>true</GenerateResourceUsePreserializedResources>
 		<GenerateResourceWarnOnBinaryFormatterUse>false</GenerateResourceWarnOnBinaryFormatterUse>
 	</PropertyGroup>
diff --git a/UoFiddler.Plugin.MultiEditor/UserControls/MultiEditorControl.cs b/UoFiddler.Plugin.MultiEditor/UserControls/MultiEditorControl.cs
index 7bda5672..63383c3d 100644
--- a/UoFiddler.Plugin.MultiEditor/UserControls/MultiEditorControl.cs
+++ b/UoFiddler.Plugin.MultiEditor/UserControls/MultiEditorControl.cs
@@ -48,7 +48,8 @@ public partial class MultiEditorControl : UserControl
         private Point _marqueeEnd;
 
         // Copy/Paste
-        private List<(ushort id, int dx, int dy, int dz)> _clipboard;
+        // Dynamic flag and extra field travel with the tile, so a paste matches what was copied.
+        private List<(ushort id, int dx, int dy, int dz, bool invisible, int extra)> _clipboard;
         private bool _isPasteMode;
 
         // Zoom
@@ -181,6 +182,7 @@ private void BTN_CreateBlank_Click(object sender, EventArgs e)
             int height = (int)numericUpDown_Size_Height.Value;
 
             _compList = new MultiEditorComponentList(width, height, this);
+            ClearTileReferences();
 
             UndoList_Clear();
 
@@ -915,7 +917,8 @@ private void PictureBoxMultiOnMouseMove(object sender, MouseEventArgs e)
             }
             else if (_isMarqueeDragging)
             {
-                _marqueeEnd = new Point(e.X + hScrollBar.Value, e.Y + vScrollBar.Value);
+                // Same zoom-aware space as the tiles, so the rectangle selects what it covers.
+                _marqueeEnd = ToScrolledSpace(e.Location);
             }
             else if (_isRectFillDragging && _compList != null)
             {
@@ -954,7 +957,7 @@ private void PictureBoxMultiOnMouseDown(object sender, MouseEventArgs e)
                 {
                     // Start marquee drag over empty space
                     _isMarqueeDragging = true;
-                    _marqueeStart = new Point(e.X + hScrollBar.Value, e.Y + vScrollBar.Value);
+                    _marqueeStart = ToScrolledSpace(e.Location);
                     _marqueeEnd = _marqueeStart;
                 }
             }
@@ -1034,7 +1037,7 @@ private void PictureBoxMultiOnMouseUp(object sender, MouseEventArgs e)
             if (_isPasteMode && e.Button == MouseButtons.Left && _clipboard != null)
             {
                 ConvertCoords(_mouseLoc, out int px, out int py, out int pz);
-                var batch = _clipboard.Select(c => (c.id, px + c.dx, py + c.dy, pz + c.dz)).ToList();
+                var batch = _clipboard.Select(c => (c.id, px + c.dx, py + c.dy, pz + c.dz, c.invisible, c.extra)).ToList();
                 _compList.TileAddBatch(batch);
                 _isPasteMode = false;
                 MaxHeightTrackBar.Minimum = _compList.ZMin;
@@ -1390,7 +1393,7 @@ private void PictureBoxMultiOnPaint(object sender, PaintEventArgs e)
             if (_isPasteMode && _clipboard != null)
             {
                 ConvertCoords(_mouseLoc, out int px, out int py, out int pz);
-                foreach (var (id, dx, dy, dz) in _clipboard)
+                foreach (var (id, dx, dy, dz, _, _) in _clipboard)
                 {
                     var ghost = new MultiTile(id, px + dx, py + dy, pz + dz, 1);
                     Bitmap ghostBmp = ghost.GetBitmap();
@@ -1679,6 +1682,7 @@ private void TreeViewMultiList_LoadFromFile(Multis.ImportType importType)
                             MultiComponentList multi = Multis.LoadFromFile(dialog.FileName, importType);
 
                             _compList = new MultiEditorComponentList(multi, this);
+                            ClearTileReferences();
 
                             UndoList_Clear();
 
@@ -1771,6 +1775,7 @@ private void TreeViewMultiList_NodeMouseDoubleClick(object sender, TreeNodeMouse
                 textBox_SaveToID.Text = e.Node.Tag.ToString();
             }
 
+            ClearTileReferences();
             UndoList_Clear();
 
             MaxHeightTrackBar.Minimum = _compList.ZMin;
@@ -1895,17 +1900,8 @@ private void Undo_onClick(object sender, EventArgs e)
             int undo = (int)item.Tag;
             _compList.Undo(undo);
 
-            MaxHeightTrackBar.Minimum = _compList.ZMin;
-            MaxHeightTrackBar.Maximum = _compList.ZMax;
-            MaxHeightTrackBar.Value = _compList.ZMax;
-
-            numericUpDown_Size_Width.Value = _compList.Width;
-            numericUpDown_Size_Height.Value = _compList.Height;
-
-            numericUpDown_Selected_X.Maximum = _compList.Width - 1;
-            numericUpDown_Selected_Y.Maximum = _compList.Height - 1;
-
-            ScrollbarsSetValue();
+            ClearTileReferences();
+            SyncControlsToList();
 
             pictureBoxMulti.Invalidate();
         }
@@ -2222,17 +2218,61 @@ private void PictureBoxDrawTiles_Select()
             }
         }
 
+        /// <summary>
+        /// Drops every reference to tiles of the previous list. Undo, redo and opening a multi
+        /// rebuild the tiles as new objects, so old references would edit tiles no longer shown.
+        /// </summary>
+        private void ClearTileReferences()
+        {
+            _selectedTiles.Clear();
+            _overlayList.Clear();
+            HoverTile = null;
+            SelectedTile = null;
+            _isPasteMode = false;
+        }
+
+        /// <summary>
+        /// Brings the size, height and selection limits in line with the current list.
+        /// </summary>
+        private void SyncControlsToList()
+        {
+            UpdateTrackBarAfterZChange();
+
+            numericUpDown_Size_Width.Value = _compList.Width;
+            numericUpDown_Size_Height.Value = _compList.Height;
+
+            numericUpDown_Selected_X.Maximum = _compList.Width - 1;
+            numericUpDown_Selected_Y.Maximum = _compList.Height - 1;
+
+            ScrollbarsSetValue();
+        }
+
+        /// <summary>
+        /// True when keyboard focus is in a text or number box, which needs its own keys
+        /// (minus, brackets, arrows, Ctrl+C/V/Z).
+        /// </summary>
+        private bool IsTextInputFocused()
+        {
+            Control focused = ActiveControl;
+            while (focused is ContainerControl { ActiveControl: not null } container)
+            {
+                focused = container.ActiveControl;
+            }
+
+            return focused is TextBoxBase or UpDownBase or ComboBox;
+        }
+
         protected override bool ProcessCmdKey(ref Message msg, Keys keyData)
         {
-            if (_compList != null)
+            if (_compList != null && (keyData == Keys.Escape || !IsTextInputFocused()))
             {
                 // Undo / Redo
                 if (keyData == (Keys.Control | Keys.Z))
                 {
                     if (_compList.UndoStep())
                     {
-                        UpdateTrackBarAfterZChange();
-                        _selectedTiles.Clear();
+                        ClearTileReferences();
+                        SyncControlsToList();
                         pictureBoxMulti.Invalidate();
                     }
 
@@ -2243,8 +2283,8 @@ protected override bool ProcessCmdKey(ref Message msg, Keys keyData)
                 {
                     if (_compList.RedoStep())
                     {
-                        UpdateTrackBarAfterZChange();
-                        _selectedTiles.Clear();
+                        ClearTileReferences();
+                        SyncControlsToList();
                         pictureBoxMulti.Invalidate();
                     }
 
@@ -2278,7 +2318,7 @@ protected override bool ProcessCmdKey(ref Message msg, Keys keyData)
                     int ox = _selectedTiles.Min(t => t.X);
                     int oy = _selectedTiles.Min(t => t.Y);
                     int oz = _selectedTiles.Min(t => t.Z);
-                    _clipboard = _selectedTiles.Select(t => (t.Id, t.X - ox, t.Y - oy, t.Z - oz)).ToList();
+                    _clipboard = _selectedTiles.Select(t => (t.Id, t.X - ox, t.Y - oy, t.Z - oz, t.Invisible, t.Extra)).ToList();
                     return true;
                 }
 
@@ -2334,18 +2374,15 @@ protected override bool ProcessCmdKey(ref Message msg, Keys keyData)
                     return true;
                 }
 
-                if (ActiveControl is not TextBox && ActiveControl is not NumericUpDown)
-                {
-                    if (keyData == Keys.S) { BTN_Select_Click(null, EventArgs.Empty); return true; }
-                    if (keyData == Keys.D) { BTN_Draw_Click(null, EventArgs.Empty); return true; }
-                    if (keyData == Keys.R) { BTN_Remove_Click(null, EventArgs.Empty); return true; }
-                    if (keyData == Keys.E) { BTN_Z_Click(null, EventArgs.Empty); return true; }
-                    if (keyData == Keys.F) { BTN_Floor.Checked = !BTN_Floor.Checked; return true; }
-                    if (keyData == Keys.P) { BTN_Pipette_Click(null, EventArgs.Empty); return true; }
-                    if (keyData == Keys.T) { BTN_Trans_Clicked(null, EventArgs.Empty); return true; }
-                    if (keyData == Keys.B) { BTN_RectFill_Click(null, EventArgs.Empty); return true; }
-                    if (keyData == Keys.L) { BTN_LineDraw_Click(null, EventArgs.Empty); return true; }
-                }
+                if (keyData == Keys.S) { BTN_Select_Click(null, EventArgs.Empty); return true; }
+                if (keyData == Keys.D) { BTN_Draw_Click(null, EventArgs.Empty); return true; }
+                if (keyData == Keys.R) { BTN_Remove_Click(null, EventArgs.Empty); return true; }
+                if (keyData == Keys.E) { BTN_Z_Click(null, EventArgs.Empty); return true; }
+                if (keyData == Keys.F) { BTN_Floor.Checked = !BTN_Floor.Checked; return true; }
+                if (keyData == Keys.P) { BTN_Pipette_Click(null, EventArgs.Empty); return true; }
+                if (keyData == Keys.T) { BTN_Trans_Clicked(null, EventArgs.Empty); return true; }
+                if (keyData == Keys.B) { BTN_RectFill_Click(null, EventArgs.Empty); return true; }
+                if (keyData == Keys.L) { BTN_LineDraw_Click(null, EventArgs.Empty); return true; }
             }
 
             return base.ProcessCmdKey(ref msg, keyData);
@@ -2405,10 +2442,7 @@ private void BTN_DynamicCheckBox_Changed(object sender, EventArgs e)
                 return;
             }
 
-            if (SelectedTile.Invisible != DynamiccheckBox.Checked)
-            {
-                SelectedTile.Invisible = DynamiccheckBox.Checked;
-            }
+            _compList.TileSetInvisible(SelectedTile, DynamiccheckBox.Checked);
         }
 
         private void BTN_ShowWalkables_Click(object sender, EventArgs e)
diff --git a/UoFiddler.Plugin.SendItem/SendItem.cs b/UoFiddler.Plugin.SendItem/SendItem.cs
index 50dd0f52..fbe8ba75 100644
--- a/UoFiddler.Plugin.SendItem/SendItem.cs
+++ b/UoFiddler.Plugin.SendItem/SendItem.cs
@@ -26,12 +26,6 @@ namespace UoFiddler.Plugin.SendItem
 {
     public class SendItemPluginBase : PluginBase
     {
-        public SendItemPluginBase()
-        {
-            _refMarker = this;
-            Events.ModifyItemsControlContextMenuEvent += EventsModifyItemsControlContextMenuEvent;
-        }
-
         private static SendItemPluginBase _refMarker;
         private static bool _overrideClick;
 
@@ -79,6 +73,10 @@ public override void Initialize()
         {
             _ = Files.RootDir;
 
+            // Done here, not in the constructor: the Manage Plugins form constructs disabled plugins too.
+            _refMarker = this;
+            Events.ModifyItemsControlContextMenuEvent += EventsModifyItemsControlContextMenuEvent;
+
             LoadXml();
             ChangeOverrideClick(OverrideClick, true);
         }
@@ -90,6 +88,7 @@ private void PlugOnDoubleClick(object sender, MouseEventArgs e)
 
         public override void Unload()
         {
+            Events.ModifyItemsControlContextMenuEvent -= EventsModifyItemsControlContextMenuEvent;
             SaveXml();
         }
 
diff --git a/UoFiddler/Classes/FiddlerOptions.cs b/UoFiddler/Classes/FiddlerOptions.cs
index 15b3d568..f562fee5 100644
--- a/UoFiddler/Classes/FiddlerOptions.cs
+++ b/UoFiddler/Classes/FiddlerOptions.cs
@@ -82,7 +82,10 @@ public static void Startup()
             MoveFiles(di.GetFiles("DynamicItems.xml", SearchOption.TopDirectoryOnly), Options.AppDataPath);
 
             di = new DirectoryInfo(Path.Combine(Application.StartupPath, "plugins"));
-            MoveFiles(di.GetFiles("*.xml", SearchOption.TopDirectoryOnly), plugInPath);
+            if (di.Exists)
+            {
+                MoveFiles(di.GetFiles("*.xml", SearchOption.TopDirectoryOnly), plugInPath);
+            }
 
             string fileName = Path.Combine(Options.AppDataPath, "Options_default.xml");
             if (!File.Exists(fileName))
@@ -299,6 +302,17 @@ public static void SaveProfile()
             _log.LogInformation("SaveProfile - done {Filename}", fileName);
         }
 
+        // Profile attributes can be missing in older or hand edited profiles; keep the fallback then.
+        private static bool ReadBool(XmlElement elem, string attribute, bool fallback)
+        {
+            return bool.TryParse(elem.GetAttribute(attribute), out bool value) ? value : fallback;
+        }
+
+        private static int ReadInt(XmlElement elem, string attribute, int fallback)
+        {
+            return int.TryParse(elem.GetAttribute(attribute), System.Globalization.NumberStyles.Integer, System.Globalization.CultureInfo.InvariantCulture, out int value) ? value : fallback;
+        }
+
         public static void LoadProfile(string filename)
         {
             _log.LogInformation("LoadProfile - start: {Filename}", filename);
@@ -313,7 +327,13 @@ public static void LoadProfile(string filename)
             XmlDocument dom = new XmlDocument();
             dom.Load(fileName);
             XmlElement xOptions = dom["Options"];
-            XmlElement elem = (XmlElement)xOptions?.SelectSingleNode("OutputPath");
+            if (xOptions == null)
+            {
+                _log.LogWarning("LoadProfile: no Options element in {Filename}", filename);
+                return;
+            }
+
+            XmlElement elem = (XmlElement)xOptions.SelectSingleNode("OutputPath");
             if (elem != null)
             {
                 Options.OutputPath = elem.GetAttribute("path");
@@ -330,14 +350,14 @@ public static void LoadProfile(string filename)
             elem = (XmlElement)xOptions.SelectSingleNode("ItemSize");
             if (elem != null)
             {
-                Options.ArtItemSizeWidth = int.Parse(elem.GetAttribute("width"));
-                Options.ArtItemSizeHeight = int.Parse(elem.GetAttribute("height"));
+                Options.ArtItemSizeWidth = ReadInt(elem, "width", Options.ArtItemSizeWidth);
+                Options.ArtItemSizeHeight = ReadInt(elem, "height", Options.ArtItemSizeHeight);
             }
 
             elem = (XmlElement)xOptions.SelectSingleNode("ItemClip");
             if (elem != null)
             {
-                Options.ArtItemClip = bool.Parse(elem.GetAttribute("active"));
+                Options.ArtItemClip = ReadBool(elem, "active", Options.ArtItemClip);
             }
 
             elem = (XmlElement)xOptions.SelectSingleNode("SaveFormat");
@@ -349,7 +369,7 @@ public static void LoadProfile(string filename)
             elem = (XmlElement)xOptions.SelectSingleNode("CacheData");
             if (elem != null)
             {
-                Files.CacheData = bool.Parse(elem.GetAttribute("active"));
+                Files.CacheData = ReadBool(elem, "active", Files.CacheData);
             }
 
             elem = (XmlElement)xOptions.SelectSingleNode("TileFocusColor");
@@ -367,7 +387,7 @@ public static void LoadProfile(string filename)
             elem = (XmlElement)xOptions.SelectSingleNode("RemoveTileBorder");
             if (elem != null)
             {
-                Options.RemoveTileBorder = bool.Parse(elem.GetAttribute("active"));
+                Options.RemoveTileBorder = ReadBool(elem, "active", Options.RemoveTileBorder);
             }
 
             elem = (XmlElement)xOptions.SelectSingleNode("PreviewBackgroundColor");
@@ -402,7 +422,7 @@ public static void LoadProfile(string filename)
             }
 
             elem = (XmlElement)xOptions.SelectSingleNode("NewMapSize");
-            if (elem != null && bool.Parse(elem.GetAttribute("active")))
+            if (elem != null && ReadBool(elem, "active", false))
             {
                 Map.Felucca.Width = 7168;
                 Map.Trammel.Width = 7168;
@@ -411,19 +431,19 @@ public static void LoadProfile(string filename)
             elem = (XmlElement)xOptions.SelectSingleNode("UseMapDiff");
             if (elem != null)
             {
-                Map.StartUpSetDiff(bool.Parse(elem.GetAttribute("active")));
+                Map.StartUpSetDiff(ReadBool(elem, "active", false));
             }
 
             elem = (XmlElement)xOptions.SelectSingleNode("PolSoundIdOffset");
             if (elem != null)
             {
-                Options.PolSoundIdOffset = bool.Parse(elem.GetAttribute("active"));
+                Options.PolSoundIdOffset = ReadBool(elem, "active", Options.PolSoundIdOffset);
             }
 
             elem = (XmlElement)xOptions.SelectSingleNode("UpdateCheck");
             if (elem != null)
             {
-                UpdateCheckOnStart = bool.Parse(elem.GetAttribute("active"));
+                UpdateCheckOnStart = ReadBool(elem, "active", UpdateCheckOnStart);
             }
 
             elem = (XmlElement)xOptions.SelectSingleNode("SendCharToLoc");
@@ -481,17 +501,19 @@ public static void LoadProfile(string filename)
 
             foreach (XmlElement xTab in xOptions.SelectNodes("TabView"))
             {
-                int viewTab = Convert.ToInt32(xTab.GetAttribute("tab"));
-                Options.ChangedViewState[viewTab] = false;
+                if (int.TryParse(xTab.GetAttribute("tab"), out int viewTab))
+                {
+                    Options.ChangedViewState[viewTab] = false;
+                }
             }
 
             elem = (XmlElement)xOptions.SelectSingleNode("ViewState");
             if (elem != null)
             {
-                StoreFormState = bool.Parse(elem.GetAttribute("Active"));
-                MaximisedForm = bool.Parse(elem.GetAttribute("Maximised"));
-                FormPosition = new Point(int.Parse(elem.GetAttribute("PositionX")), int.Parse(elem.GetAttribute("PositionY")));
-                FormSize = new Size(int.Parse(elem.GetAttribute("Width")), int.Parse(elem.GetAttribute("Height")));
+                StoreFormState = ReadBool(elem, "Active", StoreFormState);
+                MaximisedForm = ReadBool(elem, "Maximised", MaximisedForm);
+                FormPosition = new Point(ReadInt(elem, "PositionX", FormPosition.X), ReadInt(elem, "PositionY", FormPosition.Y));
+                FormSize = new Size(ReadInt(elem, "Width", FormSize.Width), ReadInt(elem, "Height", FormSize.Height));
             }
 
             elem = (XmlElement)xOptions.SelectSingleNode("TileDataDirectlySaveOnChange");
diff --git a/UoFiddler/Forms/LoadProfileForm.cs b/UoFiddler/Forms/LoadProfileForm.cs
index 38e74810..cf3efa43 100644
--- a/UoFiddler/Forms/LoadProfileForm.cs
+++ b/UoFiddler/Forms/LoadProfileForm.cs
@@ -76,6 +76,8 @@ private void LoadSelectedProfile()
             _log.LogInformation("Loading profile: {ProfileName}", Options.ProfileName);
             FiddlerOptions.LoadProfile($"{_profiles[comboBoxLoad.SelectedIndex]}.xml");
 
+            // The Enter key path closes the form without a button, so set the result here.
+            DialogResult = DialogResult.OK;
             Close();
         }
 
diff --git a/UoFiddler/Forms/MainForm.cs b/UoFiddler/Forms/MainForm.cs
index 5aeb9300..3cc9f83f 100644
--- a/UoFiddler/Forms/MainForm.cs
+++ b/UoFiddler/Forms/MainForm.cs
@@ -533,9 +533,11 @@ private void OnClosing(object sender, FormClosingEventArgs e)
                 }
             }
 
+            // RestoreBounds holds the normal size and position while the form is maximized or minimized.
+            Rectangle bounds = WindowState == FormWindowState.Normal ? Bounds : RestoreBounds;
             FiddlerOptions.MaximisedForm = WindowState == FormWindowState.Maximized;
-            FiddlerOptions.FormPosition = Location;
-            FiddlerOptions.FormSize = Size;
+            FiddlerOptions.FormPosition = bounds.Location;
+            FiddlerOptions.FormSize = bounds.Size;
 
             _log.LogInformation("MainForm - OnClosing - unloading plugins");
             GlobalPlugins.Plugins.ClosePlugins();
@@ -545,17 +547,17 @@ private void OnClosing(object sender, FormClosingEventArgs e)
 
         private static bool IsOkFormStateLocation(Point loc, Size size)
         {
-            if (loc.X < 0 || loc.Y < 0)
+            // Any screen will do, so a window closed on a second monitor opens there again.
+            var bounds = new Rectangle(loc, size);
+            foreach (Screen screen in Screen.AllScreens)
             {
-                return false;
-            }
-
-            if (loc.X + size.Width > Screen.PrimaryScreen.WorkingArea.Width)
-            {
-                return false;
+                if (screen.WorkingArea.Contains(bounds))
+                {
+                    return true;
+                }
             }
 
-            return loc.Y + size.Height <= Screen.PrimaryScreen.WorkingArea.Height;
+            return false;
         }
 
         private void ToggleView(object sender, EventArgs e)
diff --git a/UoFiddler/Forms/ManagePluginsForm.cs b/UoFiddler/Forms/ManagePluginsForm.cs
index 7738ddea..52f88dcf 100644
--- a/UoFiddler/Forms/ManagePluginsForm.cs
+++ b/UoFiddler/Forms/ManagePluginsForm.cs
@@ -10,6 +10,7 @@
  ***************************************************************************/
 
 using System;
+using System.Collections.Generic;
 using System.Drawing;
 using System.Windows.Forms;
 using Microsoft.Extensions.Logging;
@@ -23,6 +24,10 @@ public partial class ManagePluginsForm : Form
     {
         private static readonly ILogger _log = AppLog.For(typeof(ManagePluginsForm));
 
+        // Instances made only to show a plugin's name and details. They are never initialized,
+        // so they are dropped again on close and never unloaded.
+        private readonly HashSet<AvailablePlugin> _temporaryInstances = new HashSet<AvailablePlugin>();
+
         public ManagePluginsForm()
         {
             InitializeComponent();
@@ -30,14 +35,16 @@ public ManagePluginsForm()
 
             foreach (AvailablePlugin plugin in GlobalPlugins.Plugins.AvailablePlugins)
             {
-                bool loaded = true;
                 if (plugin.Instance == null)
                 {
                     _log.LogInformation("ManagePlugins - creating plugin instance: {Plugin} path: {AssemblyPath}", plugin.Type, plugin.AssemblyPath);
                     plugin.CreateInstance();
-                    loaded = false;
+                    _temporaryInstances.Add(plugin);
                 }
-                checkedListBox1.Items.Add(plugin.Instance.Name, loaded);
+
+                // The profile decides what is enabled; a change here takes effect on the next start.
+                bool enabled = Options.PluginsToLoad?.Contains(plugin.Type.ToString()) == true;
+                checkedListBox1.Items.Add(plugin.Instance.Name, enabled);
             }
         }
 
@@ -74,23 +81,24 @@ private void OnClosing(object sender, FormClosingEventArgs e)
         {
             foreach (AvailablePlugin plug in GlobalPlugins.Plugins.AvailablePlugins)
             {
-                if (Options.PluginsToLoad?.Contains(plug.Type.ToString()) == false)
-                {
-                    if (checkedListBox1.CheckedItems.Contains(plug.Instance.Name))
-                    {
-                        _log.LogInformation("ManagePlugins - adding plugin to profile: {Plugin}", plug.Type.ToString());
-                        Options.PluginsToLoad.Add(plug.Type.ToString());
-                    }
+                string type = plug.Type.ToString();
+                bool isChecked = checkedListBox1.CheckedItems.Contains(plug.Instance.Name);
+                bool enabled = Options.PluginsToLoad?.Contains(type) == true;
 
-                    plug.Instance = null;
+                if (Options.PluginsToLoad != null && isChecked && !enabled)
+                {
+                    _log.LogInformation("ManagePlugins - adding plugin to profile: {Plugin}", type);
+                    Options.PluginsToLoad.Add(type);
                 }
-                else
+                else if (Options.PluginsToLoad != null && !isChecked && enabled)
                 {
-                    if (!checkedListBox1.CheckedItems.Contains(plug.Instance.Name))
-                    {
-                        _log.LogInformation("ManagePlugins - removing plugin from profile: {Plugin}", plug.Type.ToString());
-                        Options.PluginsToLoad.Remove(plug.Type.ToString());
-                    }
+                    _log.LogInformation("ManagePlugins - removing plugin from profile: {Plugin}", type);
+                    Options.PluginsToLoad.Remove(type);
+                }
+
+                if (_temporaryInstances.Contains(plug))
+                {
+                    plug.Instance = null;
                 }
             }
         }