"Full screen" menu item and its keyboard short cut F11 stop working with Acrobat Reader. The Firefox top edge border does not hide once you have moved around in the Acrobat document. Therefore it is not possible to display PDF documents in a true full screen mode within Firefox. The auto-hide full screen mode works nicely with other Firefox windows, so apparently the Acrobat Reader add-on breaks the feature. Windows 7 64-bit.

Modified by MarkF2748