Maybe something has corrupted the interface. Try this: * http://kb.mozillazine.org/Corrupt_localstore.rdf

You can check for problems with preferences and try to rename or delete the prefs.js file and possible numbered prefs-##.js files and a possible user.js file to reset all prefs to the default values. *http://kb.mozillazine.org/Preferences_not_saved *http://kb.mozillazine.org/Resetting_preferences ----- Try to create a new profile as a test to check if your current profile is causing the problems. See "Creating a profile": *https://support.mozilla.org/kb/profile-manager-create-and-remove-firefox-profiles *http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Profile_issues If the new profile works then you can transfer some files from an existing profile to the new profile, but be careful not to copy corrupted files. *http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox