Is the following code exposing a bug in Excel?

Sub Auto_Open()

Application.Screenupdating = False

Sheets(1).Select
ActiveWindow.SmallScroll ToRight:=-100
ActiveWindow.SmallScroll Down:=-100

Range("A1:N46").Select
ActiveWindow.Zoom = True

Application.Screenupdating = True

End sub

Range("A1:N46") is the range that I want to fill the screen, whoever
opens the workbook(with whatever configuration of toolbars they have on
their screen).
On openeing this workbook there is a horrible flicker - any way to get
rid of it, or workaround it?!!

Any help greatly appreciated

Jason Quirk