I've got a problem with Firefox - in that sometimes when switchign tabs I just see the spinning wheel. After some investigation it appears I can fix this by setting browser.tabs.remote.autostart in about:config to false. However this doesn't appeared to be stored permanently i.e. when I close FireFox and reopen it - it's been set back to false. I've read onlien that modifyign the file C:\Program Files\Mozilla Firefox\defaults\pref\channel-prefs.js to add the line: pref("browser.tabs.remote.autostart", false); Should address this - but - this doesn't seem to set it to false when I start Firefox.