>That's my problem. I have to do it without get focus on my form.
>As example, I'm editing two .prg with modify command and I need to detect the changes of focus between them from my form without get focus on my form.

There are foxtools functions, wontop(), wlast() etc, winAPI GetCursorPos, GetCaret etc.
ie: Check wontop() with a timer.
Cetin