Sorry for reviving old bug report, just wanted to report that it's still an issue. Presently running TC-6, Xvesa, FLTK. The problem occurs with Firefox-official (Firefox 33.1.1) from the TC-6 repository. No add-ons installed. For whatever reason, this TC build comes with a built-in plugin called OpenH264 video codec provided by Cisco, which has been disabled. No flash or other plugins.
As above, the problem occurs when bookmarking a site that uses a long bookmark name (>54 characters). The entire bookmark dropdown list goes black, making them impossible to read unless hovering over with mouse cursor. Do not have adequate software installed at this time to provide a screenshot. The problem should be easy to reproduce. Simply open the properties of any bookmark and append a long bookmark name, select the bookmark dropdown and the list should be all black.
Simple work around is to rename the bookmark to something shorter than 54 characters. Admittedly this would rarely occur, but i've only been using TC for a couple weeks and it's already happened. Some websites create very long and descriptive default bookmark names. The work around is easy but unsure how the issue could be fixed (maybe Xvesa related), just pointing out the issue. Presently also running LTS Iceweasel in Debian and latest Firefox in Ubuntu and have never come across this problem.