I need a workaround forcing ComboxBox closeup.

I have this function and when there is no Alert, the ComboBox does not close on SelectedIndexChanged. With the Alert, on OK click, the ComboBox closes down.

        function onCustomerChanged(cmbCustomer) {

            alert("onCustomerChanged");

            var cmbProduct = grdInventory.GetEditor("Prdcod");

            cmbCustomer.SetEnabled(false);

            cmbProduct.PerformCallback(cmbCustomer.GetValue().toString(), function () {

                cmbCustomer.SetReadOnly(false);

                cmbProduct.SetSelectedIndex(0);

            });

        }

This is DevExpress. Is there a way to "cheat" that ComboBox to close? Something I can use in place of the Alert where nothing shows, but the ComboBox closes?

Without this call         

alert("onCustomerChanged");

I need to click two times on the selected item in order to close it.

Thanks