I'm having the same issue using Firefox 3 Beta 5 in Ubuntu Hardy Heron 8.04. When in fullscreen mode, it sometimes happens after clicking links on websites, but especially when clicking the drop-down menu of the adddress-bar or search-bar.
I'm having the same issue using Firefox 3 Beta 5 in Ubuntu Hardy Heron 8.04. When in fullscreen mode, it sometimes happens after clicking links on websites, but especially when clicking the drop-down menu of the adddress-bar or search-bar.