User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:18.0) Gecko/20100101 Firefox/18.0 Build ID: 20130109165101 Steps to reproduce: View any HTML5 video in full screen (eg Youtube) with the bookmarks sidebar open (I always have this open) example URL: http://www.youtube.com/watch?v=Do0_DIM2PQ8&feature=player_embedded Actual results: When exiting the fullscreen video the bookmarks sidebar is hidden and has to be reopened (ctrl-b) Expected results: The browser should have remained exactly how I left it before entering full screen - the bookmarks side bar should not have closed.