Not sure what you mean and surely this is not that much a pain to do manually.
Code would be tricky as this is a read only property but you MIGHT be able to fool PowerPoint like this:
Code:
Sub outlineView()
ActiveWindow.ViewType = ppViewNormal
If ActiveWindow.Panes(1).ViewType = ppViewThumbnails Then
Application.CommandBars.ExecuteMso ("OutlineThumbnailsShowHide")
ActiveWindow.Panes(1).Activate
DoEvents
ActivePresentation.Slides.Range.Select
End If
Application.CommandBars.ExecuteMso ("BulletsAndNumberingNumberingDialog")
End Sub