I can also confirm that this only seems to happen with Unity 5.12, not with 5.10. I checked this by booting the Ubuntu-12.04 desktop image into a live session, and started Gimp first with default Unity 5.10 and then with Unity 5.12 after installing updates and logging out and in again. So there seems to be some regression in Unity 5.12 that causes this bug.
** Tags added: regression-update -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/995916 Title: No launcher icon or Alt+Tab entry for Gimp windows To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/unity/+bug/995916/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
