ServerFilter on SubForm

[Dickie]

I have a subform which is a list of line details. I need to apply a new
serverfilter to this subform from a button on the main form.

Example, I click the button List All Lines.
It makes the subform visible and then applies the server filter which uses
the bound field on both forms.

Any help would be useful.

I have used the following code but it does not work.
Currform is set to screen.activeform and PO_Hdr_Nbr is a variable containing
the PO Hdr

Currform.[Purchase_Order_Detail].[Form].ServerFilter = "[PO_Nbr] = " &
PO_Hdr_Nbr