When a border is destroyed, the main thread was forcefully releasing D2D
resources, while the border window thread might still be trying to use
them in its message loop.
Releasing the RenderTarget on one thread while another is calling
EndDraw on it leads to a use-after-free scenario or invalid state for
the COM object, resulting in the crash.
This commit applies a fix that moves the resource cleanup logic from the
main thread to the window thread. Now, resources are only released
during the WM_DESTROY message processing, which guarantees
synchronization with other window messages like WM_PAINT.
Apparently there is a quirk of GetWindowLongPtr when querying styles. If
the style bits are genuinely 0, the API returns 0 but does not clear the
last error.
If a previous API call set an error, GetWindowLongPtr might define
"failure" as "return 0 AND GetLastError != 0".
Hence, it is important to clear the last/previous error before calling
GetWindowLongPtrW to ensure that we don't misinterpret a valid 0 return
value as an error.
Rejdukien