Private Sub Zielbox_SelectedIndexChanged(ByVal sender As System.Object, _
      ByVal e As System.EventArgs) Handles Zielbox.SelectedValueChanged
 
        DeleteBtn.Enabled = True
        CopyBtn.Enabled = False
 
        Quellbox.ClearSelected()
 
 
    End Sub
    Private Sub Quellbox_SelectedIndexChanged(ByVal sender As System.Object, _
      ByVal e As System.EventArgs) Handles Quellbox.SelectedValueChanged
        DeleteBtn.Enabled = False
        CopyBtn.Enabled = True
        Zielbox.ClearSelected()
 
    End Sub