Just for the sake of completeness: I did install skrooge with kde4-runtime installed and without it!
But it didn't make a difference, both installations show the same dysfunctional window.
(BTW, actually the window looked a bit different at the first start. There was a little window inside which I erroneously dragged out of the main window. I can't remember whether I closed it, but after that it never appeared again.)
Cool to have you, Stephane, as the project's maintainer on board, so I guess it will be much easier to diagnose what's going on here''