User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; lt; rv:1.8.1.3) Gecko/20070309 Firefox/2.0.0.3 Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; lt; rv:1.8.1.3) Gecko/20070309 Firefox/2.0.0.3 firefox begins to move the whole view 2px(maybe 1px) up and down infinate times maybe 5 times a second. Reproducible: Sometimes Steps to Reproduce: 1. Fresh install firefox 2. Customize toolbars like that: 2.1 Move bookmarks from bookmarks toolbar to the top (near tools, help...) 2.2 Delete all bookmarks from bookmarks toolbar 2.3 Disable bookmarks toolbar 3. open some web page Actual Results: Now, because there's no bookmarks firefox moves whole view up and down. Expected Results: No infinate movement

See here: http://kb.mozillazine.org/Window_shakes Long known issue, and I believe fixed Firefox 3.0, due in fall. Please use the support forums before filing bugs. http://forums.mozillazine.org/viewforum.php?f=38

2.0.0.4 and 1.5.0.12, actually.