QtCreator and File Dialog

[Erni42]

I did not find the right search words. After starting QtCreator (actual 3.5.0) and calling the "Open Project" dialog, I can't see any contant from the directory. No files, no directories. I'm sure to read something to this topic before. But i did not find it again.
I use Kubuntu with plasma 5.3, Qt 4.8.6 and qt 5.4.1 installed in parallel...

In the settings dialog there is no option for using native dialogs or something else...

Dietmar