>>I think I did have such experiences before, though it has been a while. In any case, I think I copied the methods I changed to the copy of the classlib I made, so at least my work is saved now (unless I forgot to copy something). I will check this library back in, then I would be able to replace it with my new copy.
>>
>>Thanks.
>
>So. You are using some form of Source control. You did not say so before. Most probably the file was not checked out properly.

Later that night when I was closing Virtual Box I realized, that it was me shooting myself in the foot. I think this is what happened. I opened a form in VFP session, found that it had container based class, checked out this class library and started to work on it in another VFP session. I'm not sure if I closed the form in my first session or not. In any case I was unable to save my changes and had to go through some complicated route to do so. I guess if I would have closed the extra VFP sessions, the problem didn't happen.