>>>Where is the AutoClose property? Property of what class is it?
>>
>>It's a property of Data Environment of the form.
>>
>>Looks like its irrelevant for VCX based forms.
>
>Maybe if I have time (and don't find a good explanation here) I will try to create a small form project to see if the problem will be confirmed. Somehow I think that the problem of form not closing this table is due to the fact that the table is FREE. Could it be that DE only takes care of database tables?

No. As others suggested here in the thread, check, if DE method CloseTables run. Just put some wait window there following return dodefault().