I tried to separate the boxes and the lines without result. The i is corrupt!

Sub HideShowLine2()
  Application.ScreenUpdating = False
  
  
    Dim i As Integer
    For i = 1 To 7
    
    Dim J As Integer
    For J = 7 To 8
        If ActiveSheet.CheckBoxes("Check Box " & J).Value = -4146 Then
            ActiveSheet.ChartObjects("Grafiek 2").Activate
            ActiveChart.SeriesCollection(i).Format.Line.Visible = msoFalse
    Else
      ActiveSheet.ChartObjects("Grafiek 2").Activate
      ActiveChart.SeriesCollection(i).Format.Line.Visible = msoTrue
    End If

  Next i
  Next J

  
End Sub


Sub AssignMacro()
  Application.ScreenUpdating = False
  Dim i As Integer
  For i = 7 To 14
    ActiveSheet.Shapes.Range(Array("Check Box " & i)).Select
    Selection.OnAction = "HideShowLine2"
  Next i
End Sub


I see the problem but i don't know how to solve it.

Box 1 to 7 has to trigger ActiveChart.SeriesCollection(i).Format.Line 1 to 7 of grafiek 1
Box 7 to 14 has to trigger ActiveChart.SeriesCollection(i).Format.Line 1 to 7 of grafiek 2

But i don't know how to change the second macro to setup the boxes like that.
I really like the feature because i can see witch line (flow) is causes the problem. Then i can disable the other lines and make a other chart visible to see what is causing the flow drop.