To reproduce:

1. Open MP.
2. Go to the TV section.
3. Start watching any channel, but to *do not* go to full screen so that the topbar is still available.
4. Click/"activate" the second bottom from the right (looks like a square).
--> video will sort of go full screen, but on the background surface, not properly
5. Click/"activate" the button again.
--> video will go into the mini-display in the bottom left corner (weird - I didn't think TV had a mini-display in the corner)
6. Click it again.
--> video goes back to full screen on the background surface
7. Click in the actual TV window.
--> TV will go to proper full screen

h4. Additional Information
SilentException already has a fix for this, which I have tested and confirmed.