>I think both you and Gregory are correct, as it will depend on the value of AutoYield
>
>"Specifies whether an instance of Visual FoxPro processes pending Windows events between execution of each line of user program code."
>
>The question I am not sure about the answer is if the foxpro timer creates a windows event or not. (I always assumed it is, I think it is much safer to think this way and following this assumption I never write code in a timer that uses data in the current data session, I will use a data session object inside the timer if I need to manipulate data)

Timer, just like any other object, executes its code in the datasession in which it was created (which still holds for session and form objects, which instantiate a DS first and then get created in it).

>[UPDATE]
>Actually I think you are right Jim, I've been living a lie! code is not interrupted by a timer, I just created a program with a timer and some FOR loops, and if I do not put DOEVENTS inside the loop, the timer never fires, shame on me!

Which then creates chaos when debugging: the code which would never get interrupted in real time, gets interrupted any number of times while we're stepping through it. So if timer code has any side effects which may affect the code we're debugging, we're observing the wrong event.