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[Bug]: NotifyIcon displays an empty, miniature black tooltip box when Text is string.Empty on Windows 11 #15051
Description
.NET version
.NET 10.0.11
Did it work in .NET Framework?
Not tested/verified
Did it work in any of the earlier releases of .NET Core or .NET 5+?
不明
Issue description
これが仕様であるのであれば申し訳ありません。
ツールチップを空文字を設定すると画像のように空のツールチップが表示されます。
Notifyicon.csの659行目
data.uFlags |= NOTIFY_ICON_DATA_FLAGS.NIF_TIP;
data.Tip = _text;
とありますが、正しくは
if (_text is not "")
{
data.uFlags |= NOTIFY_ICON_DATA_FLAGS.NIF_TIP;
data.Tip = _text;
}
ではないでしょうか？
Steps to reproduce
_notifyIcon.Text = string.Empty;
_notifyIcon.Icon = Resources.MemoryCleaner;
_notifyIcon.ContextMenuStrip = _contextMainItem;
_notifyIcon.Visible = true;
_notifyIcon.Text = string.Empty;
_notifyIcon.Icon = Resources.MemoryCleaner;
_notifyIcon.ContextMenuStrip = _contextMainItem;
_notifyIcon.Visible = true;
Textにstring.Emptyを設定する。
Activity
LeafShi1 commentedon Sep 8, 2026
@Yukki76 My local environment is Windows 25H2, build 26200.9106, and I haven't been able to reproduce this issue.
Please provide the following information for further verification:
Yukki76 commentedon Sep 8, 2026
The version is as shown in the image.
I'm developing a background application, and after running it for a while, hovering the mouse over the task icon displays an empty popup.
I've created a custom popup to display, and I haven't specified
NotifyIcon.Text. I also reproduced the issue usingstring.Empty.I'll observe the situation a bit longer and report back.
I apologize for the trouble.
Yukki76 commentedon Sep 17, 2026
starts, and sometimes it does not. On one occasion, the issue was noticed while the application was running in the system tray.
The source code where the issue was confirmed is available at the following link:
https://github.com/Yukki76/TrayIconTest
This is a simple program that displays the string and length of the tooltip currently set in NotifyIcon in a custom tooltip (form).
Currently, a null character (string.Empty) is set to display the custom tooltip.
Environment where the issue was confirmed:
OS: Microsoft Windows 11 Home 25H2 (OS build 26200.9457)
.NET Version: .NET 10.0.12
We apologize for bothering you during your busy schedule, but we would appreciate your assistance.
LeafShi1 commentedon Oct 12, 2026
Thanks for providing the repro project and the additional context.
I've tested the provided project multiple times but haven't been able to reproduce the issue. I also tried running the application in the system tray, but haven't observed the miniature black tooltip.
Since this seems to occur intermittently, we'll likely need more information about the conditions that trigger it before we can investigate further. If you notice any consistent pattern or additional reproduction steps, please let us know.
dotnet-policy-service commentedon Oct 26, 2026
This submission has been automatically marked as stale because it has been marked as requiring author feedback but has not had any activity for 14 days.
It will be closed if no further activity occurs within 7 days of this comment.