It hard to explain, but I will try.
I cant opereate on full screen apps in areas that are for rolling down or up panels, when the windows arent in full screen.
for example:
I had to panels on the bottom and on the top of the screen. They are autohiding.
When I run movie on youtube in full screen I cant go back to normal view using the button on the bottom. I cant use none of the buttons from bottom.

It is like that in the area of the panels its unable to operate.

Reproducible: Always

Steps to Reproduce:
1. Set panels to auto hide
2. Run any application in full screen mode
3. Try to opereate on the window in full screen in areas dedicated for panels to show.
Actual Results:  
I cant use the buttons in full screen apps when I have panels set to autohide.
When the panels are set to always visible the error dosnt occur

Expected Results:  
auto hiding panels shouldnt have any influance on the full screen application

If Isnt clearly descripted I can add a screencast.