Are you using a userChrome.js hack? If there are no .js or .xml files in the chrome folder, then you are not using a userChrome.js hack.
Are you using the user.js file in the profile folder? A syntax error in the user.js file could cause problems.
Is there another file besides the channel-prefs.js file in the <install folder>\defaults\pref folder? A syntax error in these files could cause problems.
Exoteeth had a odd problem with the userChrome.css file.
More info: http://forums.mozillazine.org/viewtopic ... #p14822439Exoteeth wrote:It turns out it had to do with the prefs file, which I substituted from another FF build. What happens is I didn't have FF setup the same as the other build, so the substituted prefs file caused a lot of functions to not work, including CSS.