There was a bug with DOEVENTS in VFP6 that caused it to execute slowly. I suspect the fix to that is causing the change in behavior you are seeing.

I can reproduce what you are seeing, but I found a pretty simple workaround that seems to work OK for me... I tested using genmenu.prg, in the home directory, which is a pretty big program (~2600 lines). I think this is a timing issue. It looks like the Ctrl+C is being executed before the text is fully selected by the Ctrl+A.

Try this in your proc that gets called by your OKL:

KEYBOARD "{Ctrl+A}{pause .1}{Ctrl+C}"
DOEVENTS

This works fine for me.

I hope this helps!