[BUG] Claude Desktop (Windows 11): UI stops responding (clicks ignored, window cannot be dragged/resized, stuck at right screen edge) on a single external display; Windows logs Application Hang for claude.exe

Summary

On a laptop with an internal 150%-scaled panel and an external 100%-scaled monitor, Claude Desktop became progressively hard to use after switching display mode to "Second screen only" (external monitor only) with the app in full screen: left clicks were often ignored or needed two attempts, and selecting a word by click/double-click failed. At one point the window was stuck against the right edge of the screen, partially off-screen, and could not be moved, resized, or minimized. The only way out was End task in Task Manager. Windows logged an Application Hang for claude.exe at that moment. After relaunching, with two displays in Extend mode, clicks and text selection were normal.

Environment

• Windows 11 Home Single Language, build 10.0.26200
• Claude Desktop (MSIX) 2.31226.0.0 x64, bundled Claude Code 2.1.293
• Lenovo laptop, NVIDIA GeForce RTX 4070 Laptop GPU, driver 32.0.16.1088 (2026-07-22); Intel iGPU not present (discrete-GPU-only mode)
• Internal panel 2560x1600 @ 240 Hz, Windows scale 150%; external ASUS 2560x1440 at 100% (mixed DPI)
• Mouse: Logitech MX Master 3S on a Logi Bolt receiver, battery full (an earlier unrelated low-battery/Bluetooth lag problem had already been fixed)
• Also running: NVIDIA App overlay (5 "NVIDIA Overlay" processes), Logi Options+ agent, Tobii service, Nahimic. Not yet tested whether any of them contribute.

Evidence (from the affected machine, 2026-10-09, local time UTC+7)

1. Windows Event Log, Application: Application Hang, Event ID 1002 at 22:02:03: "The program claude.exe version 2.31226.0.0 stopped interacting with Windows and was closed." Accompanied by Windows Error Reporting 1001 entries (22:02:02 and 22:02:08), event name MoAppHang, package Claude_2.31226.0.0_x64__pzs8sxrjxfjjc. The timestamps match the moment the user ended the task. No Crashpad reports exist, so this was a hang, not a crash. This was the only such event in the previous 4 days.
2. Task Manager before the kill: "Claude (18)" = 11 Claude + 4 Claude Code + cowork-svc + Runtime Broker + 1 efficiency-mode process, about 1.4 GB total, CPU about 1.4%. System memory was 63% of 31.8 GB, so not CPU-bound or out of memory.
3. Window enumeration (user32 EnumWindows, run in Extend mode shortly before the app was killed) found no stray full-screen or topmost transparent overlay window.
4. No GPU driver reset or TDR events in the previous 14 days. No per-app compatibility or GPU-preference overrides for Claude.exe.

What I could not isolate

• Whether the trigger is full screen vs. maximized, the display-mode switch (Extend -> Second screen only), mixed DPI, or a third-party overlay. Other apps (Chrome, Codex) were fine in Extend mode; they were not tested in Second screen only.
• Not reproduced on demand yet.

Expected behavior

The window stays responsive and movable after a display topology change, or recovers (e.g., re-clamps to the visible area) instead of freezing.

Possibly related (not verified as the same cause)

• #99142 (Linux): main webview hangs with a very long Code session; kill and reload leaves window frozen
• #88667 (Windows, closed): Built-in Browser pane loading a challenge page crashes the GPU process and hangs the whole app