The browser appears to be displaying the list of a user's bookmarks by redrawing the bookmark list over and over again, expanding the bookmark display once for each line in the list. It also does this whenever it displays a bookmark submenu. While this is bad in itself (it takes a length of time proportional to the square of the number of bookmarks) it gets even worse if the bookmark list is too long to fit on the screen; each time the bookmark list is displayed, it gets repositioned on the screen in the same place, causing a lot of flashing of the part of the screen above the Mozilla window. It took me ten seconds from rolling my mouse over "Bookmarks" to actually having my bookmarks completely displayed. The same thing happens for bookmark submenus. It doesn't appear to happen after the first time the bookmark menu or submenu is accessed. (Please ignore any funny stuff from my User-agent; I use Junkbuster.)

good bug but if you are referring to the toplevel Bookmarks menu then this would be a dupe of at least bug 21477 *** This bug has been marked as a duplicate of 21477 ***

VERIFIED Dupe