1. Run DragNDrop demo application
2. Drag one image from first window
3. While dragging the image to the second window press Alt+F4
4. Keep mouse moving or just drop the image anywhere

Result: Application crashes.

It not reproducible on Window, because Qt event loop is blocked, by Qt Doc:

Note: On Linux and macOS, the drag and drop operation can take some time, but this function does not block the event loop. Other events are still delivered to the application while the operation is performed. On Windows, the Qt event loop is blocked during the operation.