>> reassign all Column ControlSources again. It works just fine both in VFP 3 and 5.

Yes... if you reassign the Column ControlSources again then all will be well. However, in prior threads I had misunderstood the need to do this, perhaps because at the time the columns in my grid exactly matched the fields in the table. So there was no need to explicitly reassign Column ControlSources again. I thought all that was necessary was:

Grid.RecordSource=""
Regenerate cursor/table
Grid.Recordsource=aliasname

...without needing to respecify Column ControlSources.