PyQt5 - Second Window Threading

Question

Moin, I'm new to all this, so please be paitient. My search was not successful...

I have in PyQT5 main Window a thread updating the GUI. With app.processEvents() in the thread loop everything works fine.

Now I open from this window a new window as a Form and try to do the same but there is no reference to the main app eventloop. So is the thread itself working in the thread loop and updating the GUI but is not responding to connected signals or slots.

How can I fix this?

Thank you very much.