>>James,
>>
>>ThisForm.DatasessionId = loFormA.DataSessionID
>>
>>or:
>>
>>SET DATASESSION TO (loFormA.DataSessionID)
>
>I've just discovered that if I do that, my form's grid loses RecordSource. Take care of that.

That's because the recordsource no longer exists -- you are now in a different datasession. You want to set the datasession before the grid initializes, such as in the LOAD method.