>>>>>What I changed now is I instantiate the container in the INIT method of the form, rather than dropping it on the form.
>>>>>
>>>>>This way, I have no problem.
>>>>
>>>>Perhaps in the former case you don't have the table (or cursor) open when your container initializes. If that would be the case, you would receive run-time errors.
>>>
>>>I thought something along those lines too. But the cursor is initialized in LOAD method. And the way I discovered the problem was when I was setting very bogus values in the ControlSource of the textboxes of the container. But I would never get a run-time error.
>>
>>Something is resetting the ControlSource. Did you try to put some test messagebox for the controlsource in question?
>
>No, I didn't put any messagebox() because I don't know how to put a messagebox to check the ControlSource. That is, ControlSource is a property and you can only put a messagebox into a method.

Right. Put it in the Init event of the form.