The menu is considered a video source.
I always have the program Fraps running. This gives the fps for video games. It also displays the fps for videos. The frame rate is displayed in every menu/drop box of firefox 4. Why is firefox now a video source? Don't blame this on fraps. I've never had this problem with previous versions.
Wšě wotmołwy (1)
Do you have that problem when running in the Firefox SafeMode?
A troubleshooting mode.
You can open the Firefox 4.0 SafeMode by holding the Shft key when you use the Firefox desktop or Start menu shortcut. Or use the Help menu item, click on Restart with Add-ons Disabled... while Firefox is running.
To exit the Firefox Safe Mode, just close Firefox and wait a few seconds before using the Firefox shortcut to open it again.
If not, see this:
http://support.mozilla.com/en-US/kb/troubleshooting+extensions+and+themes