Ok, here is what we found with my colleague Ambrish, who is a great programmer:

When I start my form, I have all controls (except for two date controls, it's another thread's topic) bound. In the form's init I have the following code:

	if empty(m.tcBatch_Imports_pk)
		.setall('controlsource','')		

The reason I did it was the behavior of the combobox when its RowSource is an array. If the value of the combobox is empty and it's not in the list, it adds the blank line as the last item in the list. My manager noticed this and objected. Thus I unbound my controls in run-time and put lots of extra-logic to handle them properly.

But now the editbox starts to show the behavior I noted. In other words, if the editbox was once bound and you try to programmatically set its controlsource to "", it now doesn't save the value. I would consider this behavior as a bug.

Thanks for listening and your consolations/ condolenses are warmly accepted <g>