Thanks Timo, Using xenial-proposed and running sudo apt-get install xserver-xorg-core/xenial-proposed fixed it for me also (the above command also updated xserver-common)
-- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to xorg-server in 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/xorg-server/+bug/1780664/+subscriptions _______________________________________________ Mailing list: https://launchpad.net/~ubuntu-x-swat Post to : ubuntu-x-swat@lists.launchpad.net Unsubscribe : https://launchpad.net/~ubuntu-x-swat More help : https://help.launchpad.net/ListHelp