I also experienced this problem, and upgrading xserver-xorg-core and xserver-common fixed it. So, it is rather a mesa/xorg-server incompatibilty?
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1780664 Title: Recent libgl-mesa graphics update prevents drop down list menu appearing in apps like firefox three line/bar menu icon To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/mesa/+bug/1780664/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs