single video screen size jump when clicked

Steps to reproduce:
1. open http://octestallinone.virtuos.uos.de:8080/engage/theodul/ui/core.html?id=9df59d29-0c4c-4dc8-b1a4-d6ffcc39f1c8
2. click on video

Actual Results:
video screen size toggles

Expected Results:
video screen size stays same

Workaround (if any):
I suspect changing the width of videoFocusedPiP in desktop.css from 100% to 99.5% will fix this.