>>
>>It's stupid, isn't it? It's been a fox problem ever since there were PRG files. I've not yet heard a good explanation as to why it happens.
>
>It is a bit odd. It has happened to me before, but it was so long ago that I had forgotten.

It can even happen if you rebuild a project and check 'Recompile all Files'. It may or may not really recompile them. I've never looked to see if that was on a bug list but it has been a bug in every version of VFP.