subform requery

[kingsgambit]

I have posted a simular question before but did not explain propely.

I have a combo box on the main form, and one on a subform.
By selecting a category in the main form combo, when I select the combo on the subform I want to show only the ideas in that category.
The subform combo box has a query attached to it where I put the main combo box in the criteria.