Generating a own Popup

No idea how this happend i will post and check it this time

please build your panel as a main window instead of a dialog

OK this worked and we got rid of the type error, if i start i now i get a attribute error: object has no attribute 'PREFS_' , i hope you dont get frustraded with me its all very new for me. I really appreciate your work with me. And it means a lot.

Ok I edited your handler file - I should have explained how to combine the code.
I didn't remove your popup code but it's not used. 
I used your modified qtdragon_hd.ui file
I made a sample vacuum panel based as a mainwindow with just an LED in it.

I confirmed this works on my system

This is interresting with your files i still get the error message:

AttributeError: 'MainPage' object has no attribute 'PREFS_'

If you run linuxcnc from a terminal then there should be more information on that error.

it's not enough for me to track it down