Before QT5 I could always see in the headline of dolphin, whether it was opened
as SU or as a normal user. (So I think this as a regression.)

Actually it is only mentioned there, when dolphin is started as SU. After
opening a new file the headline is the same as a normal user.

If during compilation I have opened both kinds of dolphin side by side, I need
to see a obviously difference between the two windows. There are some kinds of
workaround to find out the difference, but they are annoying.

I tried to make two screen-shots, but the difference is hardly to be seen,
because if I make a screen-shot, dolphin is not the inactive window.
But this could be reproduced very easy by everyone.