shell freezes when moving the mouse over the time slider of a not-on-top vlc instance playing media

When moving the mouse over the time slider of vlc when playing a file, the system freezes for the duration of the media file. The mouse does not move, the keyboard does not work, nothing works. Only resetting the machine or waiting for the media to end works.

The attached code is a minimal test application. code.zip

Execute ./run.sh and move your mouse slowly over the slider without clicking anywhere. The shell will freeze. The run.sh script should unfreeze the shell after 10s.