debugging gui's with the stepper (LWW)

Hopefully I'm missing something obvious or an RTFM, but if anyone knows how to do this correctly, please let me know...

I'm debugging a complicated capi GUI on LWW.

I set breakpoints in the callback code using the red-dot in the editor toolbar.

About half of the time, when the breakpoint is hit, the stepper window appears and then the system goes nuts and hits an out-of-stack condition (my impression is that the LWW winmain continues to process windows events - e.g. mouse moves over the pinboard - all of which lead to further breaks until the stack dies). It *seems* that the only way out of this is to kill LWW.

Is there a flag to suspend event delivery to the program under test, while the stepper is up?

Is there some other preferred way to debug this windows-y stuff which avoids this problem?

tia

pt