Prior to Firefox 4, the Mac version didn’t display favicons beside items on the Bookmarks Toolbar, unlike its Windows counterpart. I’ve become accustomed to this behavior, as it uses significantly less space. (I tend to use the Bookmarks Toolbar not just for frequently-used links and bookmarklets, but as a sort of “in tray” for things I need to keep an eye on temporarily.)
Some people will probably be happy about the addition of the favicons in Firefox 4, but if you’re like me you prefer to cram as many three to five letter bookmarks in as possible, which is significantly less with the icons included. But what can be done about it?
Fortunately, someone has already whipped-up a handy extension to revert back to a text-based bookmark bar. You don’t even need to restart your browser after installing it.
Bookmarks Deiconizer [Firefox Add-ons]