The description/title of this only speaks of this happening on update. I am getting this on every restart of the browser (as described in Bug #784542, which was set as a duplicate of this). Perhaps the title of this report should be changed to say restart?
I think from comment 17 that this is known to be on restart and not on upgrade. But to make sure there is no misunderstanding, here are the steps I take to reproduce this: 1. Start firefox, enter about:config, set middlemouse.contentLoadURL to true 2. middlemouse-paste a URL to a window, it loads the URL () 3. Stop firefox, check the 'prefs.js' file: $ grep middle prefs.js user_pref("middlemouse.contentLoadURL", true); 4. Start firefox, the setting is gone from the about:config and the 'prefs.js' file: $ grep middle prefs.js $ 5. middlemouse-paste a URL to a window, it does nothing. I can get this working by disabling the "Ubuntu Firefox Modifications" add-on. Not sure why that did not work for the reporter of Bug #784542. Possibly that some other setting is in conflict? I normally disable: browser.tabs.opentabfor.middleclick middlemouse.openNewWindow -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/548866 Title: forgets middlemouse.contentLoadURL on upgrade -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs