I have been working on this problem for a LONG time.
Its a compatibility issue with the browser + plugins.
Here's what I did
A workaround that accidentally turned out to be quite handy.
It may or maynot be the "right way" but the only way i could find... anywhere.
Set second display (tv, monitor, whatnot) as "Seperate Xserver"
- this may temporarily screw up Hardware Composition.
Check xorg.conf for any errors.
You Might not be able to run 3d Shells (gnome3, unity3d, etwill be able to run unity fallback, gnome flashback metacity, etc on the primary monitor. The aux monitor may be a naked Xserver which you can not drag windows onto.
Terminal commands... I think, someone correct me if im wrong.
DISPLAY=:0.1 xterm &
gets you a basic xterm on the second screen.
Or you can...
DISPLAY=:0.1 startlxde &
For me, ran light desktop on the second screen without issues.
Its handy because the second display can run another user, completely seperated from the main desktop. I use it for chrooting and virtual machines.