If (ws.Dialogbox("(Dialog_Erp_Listen)", true, true, false, false, True, False, "Dialog Auwahl Steuerschlüssel", dialogDoc, true, false, True) = true) Then
Der rote Parameter ist noFieldUpdate
Boolean. Optional. Specify True if you don't want to pass any edits from the dialog box to the underlying form (for example, if you're passing the edits somewhere else in a Queryclose script for the dialog box form). If you specify False or omit this parameter, the edits are passed to the underlying form.
Vielleicht mal mit False probieren ...