Filter a Form Based on a Field in a Subform

[Jaybird]

Okay, I've been to Allen Browne's site and used his method, but my
AfterUpdate event keeps puking on the line that goes: Me.RecordSource =
strSQL. I don't know what I'm doing wrong. I have a form [Order Entry5]
with a subform [tblOrderDetails]. I recently normalized the table structure
and everything has gone haywire. We often need to filter our records based
on fields in the subform. (Previously all contained in one table.) Now
every filter method I use returns only one filtered record. Now I've tried
Allen's method, and I'm even more lost. The code I normally use goes like
this:

If IsNull(Me.cbofilterbyTool) Then
Me.FilterOn = False
Else
Me.Filter = "[Order Number] = """ & Me.cbofilterbyTool & """"
Me.FilterOn = True
End If

But this only returns one record. The row source for the combobox goes like
this:

SELECT DISTINCT tblOrderDetails.[Tool #], [Order Entry5].[Order Number]
FROM [Order Entry5] INNER JOIN tblOrderDetails ON [Order Entry5].[Order
Number] = tblOrderDetails.[Order Number]
WHERE (((tblOrderDetails.[Tool #]) Is Not Null))
ORDER BY tblOrderDetails.[Tool #];