Private Sub Form_KeyDown(KeyCode As Integer, Shift As Integer)
  If Me.ActiveControl Is Grid1 Then
    Select Case KeyCode
      Case vbKeyReturn
        With Grid1
          If .IsEditMode = 0  And .IsFilterMode = False Then
            ' EditMode starten
            KeyCode = 0
            .DoEdit Grid1.Row, 1
          ElseIf .IsFilterMode = True Then
            ' Filtereingabe übernehmen
            .SendKeys vbKeyReturn, 0
 
          Else
            ' Im EditMode per ENTER zur nächsten Spalte wechseln
            KeyCode = 0
            SendKeys "{TAB}"
          End If
        End With
    End Select
  End If
End Sub

KeyCode = 0
SendKeys "{TAB}"

KeyCode=vbKeytab