[REG: 5.11->5.12] Crash when starting to drag in some cases

#4 0x7f97a218e1b3 QCursor::shape()
#5 0x7f97a21c05df QBasicDrag::updateCursor()
#6 0x7f97980bd07c QXcbDrag::handle_xdnd_status()
#7 0x7f97980bd870 QXcbDrag::handle_xdnd_position()
#8 0x7f97980c09ca QXcbDrag::move()
#9 0x7f97a21bf551 QBasicDrag::eventFilter()
#10 0x7f97980c1443 QXcbDrag::eventFilter()