Conflict with Tab Utilities Rated 5 out of 5 stars
Conflict with Tab Utilities 1.0.1 in my computer.
I customize appearance by tab utilities(resize tab width, remove "new tab" button, etc.) .
After I restart firefox, all settings about appearance become ineffective.
Uninstalled Proxy Selector, appearance setting work fine.
Tab utilities 1.0.2 fixed the conflict