[AccessD] Query expression refers to column(1) on a form

So this is weird, I know I've done this before, I've just been away from
Access for too long (I think).

I assumed that I can create an expression in a query that would refer to a
column of a combo box on a form as such:

Expr1: Forms![frmBuild]![cboBuildType].Column(1)

I get an error when I try to run the query: Undefined Function 'Expr1:
Forms![frmBuild]![cboBuildType].Column' in experession

(notice the column number is missing)

When I enter  ? Forms![frmBuild]![cboBuildType].Column(1) in the immediate
window, it displays the value as expected

I made a work around to get this going by creating a public function and
calling it as such:

Expr2: GetBatchName()


Public Function GetBatchName()
    GetBatchName = Forms![frmBuild]![cboBuildType].Column(1) & " " &
Format(Forms![frmBuild]![cboMonth].Column(2), "yyyymmdd")
End Function

I know, I know, there isn't any error handling, just testing it out...

Anyway, what am I forgetting?

It's been a  while.

D