I have a form named frm_TicketViewer, with a text box named fk_StatusCodeID. In a query, I’m able to successfully set the WHERE clause to:
[Forms].[frm_TicketView].[fk_StatusCodeID]
…and all is well.
Now I’ve dropped frm_TicketViewer on a page in a tab control in another form, and need to change the WHERE clause accordingly. Here be dragons. 
The new form is named frm_Main, the tab control is named tabMain, and the page on which the original form was dropped is named pgOverview. So, I’ve tried a thousand and one permutations and am now turning to the knowledgable folks here. Here are some examples of what doesn’t work. Please ignore the continuation character in the first example:
[Forms].[frm_Main].[tabMain].[Pages].[pgOverview].[Subforms].[frm_TicketView]. _ [fk_StatusCodeID]
[Forms].[frm_Main].[tabMain].[pgOverview].[frm_TicketView].[fk_StatusCodeID]
I wasn’t using a tab control, and you don’t have to reference them anyhow, but the behavior is quite plain to see. What makes it even more interesting is that it doesn’t work even if you slavishly follow the MSKB instructions and include the subform.Form reference like this:
The MSKB says you can do this, and you certainly could in earlier versions. This isn’t even very deep nesting. I wonder what’s going on here?
If I use a function in the query to cast the value as a particular datatype or use Eval(), then I get a value in the query. That doesn’t make any sense to me, but it seems to work. Give it a try. The field I was testing for was a date, so I used the CDate function in the query on the control value from the subform and that seems to work. 
I suspect this truly is the result of the changes in the query engine in A2k and later.
