Thanks for the detailed Explanation and the Code.
1. First I added the "QApplication.processEvents()" in my Code, and it mainly did what I Need (not really, the Code ran, GUI kept Control, but only in the tab I had been in when starting the program part which better shoud be run as a thread.
Anyway it proved that iis working
2. Second tried to adapt it to my Needs, but the GUI lost Control, and the program crashed in NIRWANA
3.THIRD, I created a new Project an entered your Code with CUT and PASTE. The windoe startet with "START", the Counter proceeded - until I clicked the DANGER button - GUI lost Control completely, the program crashed in NIRWANA.
I am running python 3.6.2 (32 bit) in a Windows 10 Environment (64 bit) in the pycharm development System.
I also tried in thesde provided bypython, the same result.
Is it my configuration?
Thanks in advance