The title bar's drag area is painted before its buttons and was matched
first, so Windows saw a caption over minimize, maximize and close and
started a window drag on every click.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
The window procedure records WM_DESTROY, revokes drag-drop while the
handle is valid and drops the activation callback; Drop leaves a
destroyed window alone. A dispatch after quit logs at debug.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
ZacharyZhang-NYandClaude Opus 5.5