Confirmed (on wily too). Flatten mode is broken, but more weird is that this bug only occurs in Unity8 (not in the Mir demo servers)...
As a workaround, you can use: gimp --no-splash And then for the best experience go: Windows > Single-Window Mode ** Changed in: xorg-server (Ubuntu) Status: New => Confirmed ** Also affects: unity8 (Ubuntu) Importance: Undecided Status: New ** Changed in: unity8 (Ubuntu) Status: New => Confirmed -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to xorg-server in Ubuntu. https://bugs.launchpad.net/bugs/1501346 Title: Gimp fails to start w/ Xmir running in '-rootless -flatten' mode under Unity 8 Status in unity8 package in Ubuntu: Confirmed Status in xorg-server package in Ubuntu: Confirmed Bug description: I'm trying to run Gimp in a Vivid + overlay PPA Unity 8 desktop session using Xmir from the overlay PPA with the '-rootless -flatten' Xmir options. Gimp fails to start in this situation. I've attached the application and unity8 log files. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/unity8/+bug/1501346/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp