Ok, I've traced this down to bug #1675448 being the root of the issue. Xmir is started no matter what and if an application natively supports Mir such as a Gtk or Qt app, then there are multiple connections to Mir, which is what the aforementioned bug is about.
So a decision needs to be made. Either bug #1675448 needs to be fixed or we need to revert the Gtk probing order back and just use xmir for the time being. The longer term solution of only starting xmir when it is actually needed along with Mir supported toolkits probing for Mir first is the final solution (see bug #1672931). But that won't be done in time for the Zesty release, hence the other options presented above:) -- 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/1675364 Title: [regression] GTK and KDE apps fail to start under Unity8 (without gnome-session running) To manage notifications about this bug go to: https://bugs.launchpad.net/canonical-devices-system-image/+bug/1675364/+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