Nothing has changed in Firefox for a while now, so I guess this is triggered by HUD changes last week. Could you attach gdb to Firefox and get a backtrace whilst it is hung?
Note that we deliberately don't export dbusmenu objects for a menu until it appears on screen for the first time, to avoid this type of issue with large menus (which also affects Chrome too - see bug 801699, which is pretty much the same issue), as we used to get reports of Firefox hanging for 10-15 seconds when opening the bookmarks menu for the first time -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/964584 Title: Firefox hangs temporarily everytimes it receives the focus To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/firefox/+bug/964584/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
