Unfortunately, KDE became permanently corrupted. The same behavior in comment 1 happened and I had to reinstall Kubuntu 15.04.
Because the same behavior in comment 1 happened, after I had restarted in comment 6, you should pay attention to crash information.
I made it a duplicate of bug 342438, because DrKonqi said so and asked if I want to attack crash information to this bug. I don't know if it's the right thing.
Unfortunately, KDE became permanently corrupted. The same behavior in comment 1 happened and I had to reinstall Kubuntu 15.04.
Because the same behavior in comment 1 happened, after I had restarted in comment 6, you should pay attention to crash information.
I made it a duplicate of bug 342438, because DrKonqi said so and asked if I want to attack crash information to this bug. I don't know if it's the right thing.