Combo box issue

[Zatatat]

Hello all,

This is my first post, and I'm looking forward for many more.

I have a form with a subform and combo boxes in the subform that are not working properly. My issue is that when I select an ItemNo I will get the correct list of PONo's in the PONo combo box, but after selecting the correct PONo, all the previous PONo records will get the same PONo I just selected. I need to be able to select a PONo for the current ItemNo and keep the previous records intact.

Main form: ShippingOrderForm, Subform: ShippingOrderDetailsForm
My table is PurchaseOrderODetails, the fields are PONo, ItemNo, BatchNo, Pallets, Weight, QtyRec

1st combo: ItemNo (record source: SELECT DISTINCT qry_ItemByBatch.ItemNo FROM qry_ItemByBatch ORDER BY qry_ItemByBatch.ItemNo; ) (Private Sub ItemNo_AfterUpdate()
Me.PONo.Requery End Sub)
2nd combo PONo (record source: SELECT DISTINCT [PONo] FROM PurchaseOrderODetails WHERE ((PurchaseOrderODetails.ItemNo)=Forms!ShippingOrde rForm!ShippingOrderDetailsForm.Form!ItemNo); )

Thanks in advance for your help.