Detail Line objects problem

[Langton]

I've created a subform that is a continuous form that looks like the following:

ComboBoxA (FieldA) - ComboBoxB (FieldB) - ComboBoxC (FieldC)
---------------------------------------------------------------------------
ComboBoxA (FieldA) - ComboBoxB (FieldB) - ComboBoxC (FieldC)
---------------------------------------------------------------------------
Etc.

The ComboBoxA List is populated by a query that is the same for every record.
The ComboBoxB List should be populated based on ComboBoxA value.
The ComboBoxC List should be populated based on ComboBoxB value.

The first record in the subform works as expected.
All subsequent records appear to be taking the values (ComboBoxA and
ComboBoxB) from the first record in the subform, regardless of what record I
am operating on.
In the query for ComboBoxB, the condition is "Like [cmbBoxB]" (similar for
comboC).
What do I need to change the LIKE condition to so that it looks at the
current record rather than the first record on the form?

Thanks.