Since upgrading to Natty, some of the icons in Firefox 4 have stopped showing. Speifically, the Back, Forward, and Close Tab buttons (perhaps others). This is in Gnome 2. Is there a way to get the icons back?
For some reason, icons don't show up in 32-bit Firefox versions on 64-bit Ubuntu 11.04 (at least on my system). I'm guessing this is what you're seeing.
You can fix it simply by running a 64-bit version of Firefox. You can download the latest version, Firefox 5, from here: https://ftp.mozilla.org/pub/mozilla.org/firefox/releases/5.0/linux-x86_64/en-US/
You can extract that to e.g. $HOME/programs/firefox/, and then symlink its "firefox" binary into $HOME/bin/ -- that should make this downloaded version be run preferentially over your other version, when you (or your gnome menu) invoke "firefox".