[PyQt] Strange crash with pan on qtghraphichview

[Matteo Boscolo]

  Hi All,
I got some strange crash in my qt open source application PythonCAD.

I have implemented QGraphicsView and QGraphicsScene to render the line 
arc ellipse .. of my application.
Randomly I have some crash from the qt library and I can't make any 
debug on it because the crash is not on the python code, and no error is 
raised from the framework, I have just a crash and the application goes down

Can anybody help me on this issue ?
Regards,
Matteo