Nemtom, talán valami ilyesmi:

Private Sub Workbook_SheetActivate(ByVal Sh As Object)
    Application.EnableEvents = False
    Application.ScreenUpdating = False
    If Sh.Name <> "Munka1" Then
        If Sh.Index > 5 Then
            ThisWorkbook.Worksheets("Munka1").Move before:=Sh
        Else
            ThisWorkbook.Worksheets("Munka1").Move before:=ThisWorkbook.Worksheets(1)
        End If
        Sh.Activate
    End If
    Application.ScreenUpdating = True
    Application.EnableEvents = True
End Sub