>>IF _VFP.StartMode == 0
>> SET ASSERTS ON
>> m.pnCallMethod = m.pnCallMethod + 1
>> ASSERT m.pnCallMethod # 2 && or something similar just the condition must be .f. when you want to stop
>>ENDIF
>>
>
>Doesn't work for me :(

I have no more ideas :o(
Mey be in Deactivate Event of the page (or whereever BEGIN TRASNACTION is happen) you can comment these lines or put this logic (not tested):

IF _VFP.StartMode # 0
   BEGIN TRANSACTION
ENDIF


*****


IF _VFP.StartMode # 0
   END TRANSACTION
ENDIF

Just to avoid error when REQUERY() is issued.
And then you can use the debuger :o) (I hope)