Windows: cascading ghost window frames and Terminal taskbar preview spam #825

Symptoms

On a Windows machine running the packaged Munder Difflin v0.4.14 (Electron 32.3.3), the operator reported two UI symptoms during a long-running session:

1. Multiple translucent native window frames (title-bar minimize/maximize/close controls visible) cascade diagonally over the Central de Comando / Conexões content.
2. A taskbar hover view shows many entries all titled Terminal, creating the impression that terminal windows are being spawned repeatedly.

Triage evidence

• A screenshot confirms the cascading frames, but does not establish whether they are real BrowserWindows or stale DWM/compositor frames.
• At a later read-only process/window inspection, Munder had one visible top-level window and its normal Electron GPU, renderer, and utility processes. No Windows Terminal window/process was present at that point. This does not establish what existed at screenshot time.
• The terminal screenshot resembles the grouped taskbar hover preview. It may be previews of existing console windows rather than an app loop; this remains unverified.
• Installed app build: v0.4.14, Electron 32.3.3. The available checkout is a different version (package metadata v0.4.6), so its source behavior cannot be treated as proof of the packaged build's behavior.

Request

Please investigate on the current Windows release: determine whether the overlays come from duplicate BrowserWindows, native window geometry/drag handling, or DWM/GPU composition; and whether taskbar Terminal previews correspond to PTYs/console windows being opened repeatedly. Add a bounded diagnostic/guard if the app is creating windows unexpectedly. The report was intentionally sanitized; no screenshot or internal host details are attached.

Reproduction details still needed

Windows build, GPU and driver, monitor count/scaling, exact action preceding the cascade, and whether the taskbar popup disappears on Esc/moving the pointer away.