PythonCard - My app stuck when button clicked

[daved170]

Hi there,
I'm newbie in pythonCard.
I have an application with 2 buttons : START , STOP
Start execute a while(1) loop that execute my calculations.
Stop suppose to raise a flag that will end that loop.

Whenever I pish the START button my GUI is stuck. the calculation
executes but I can't push the STOP button.

I added thread that START start a thread that execute my calculations.
I also added a Global variable that will hold the indication if the
loop should continue.
The problem now is that the thread ignore that variable and loop
forever.

Is there a simple way to make sure that the GUI won't stuck (without
threads)?
And if there isn't such way I would appriciet it very much if anyone
could post an example of how to make my thread read that variable
Thanks
Dave