If e.ColumnIndex = 6 Then
            Dim rect As Rectangle = DGV_Massen.GetCellDisplayRectangle( _
              e.ColumnIndex, e.RowIndex, False)
            With TB_W1
                .Top = SplitContainer1.Top + SplitContainer1.Panel2.Top + _
                  DGV_Massen.Top + rect.Top + UF_DGV_Eingabe.Height + 2
                .Left = rect.Left
                If .Visible = False Then .Visible = True
                .BringToFront()
                .BackColor = Color.BlueViolet ' zum testen
                .Focus()
            End With
 
        End If

Danke für die Hilfe

Gruß Christian