I have a requirement to list for my users the number of all their slides that
contain custom animations.   (Not the *count* of such slides, but the
slidenumbers themsleves.)

The following code fails in PPT 2007 and 2003 as well-- it doesn't recognize
a slide whose animation consists solely of a Disappear effect.  To test this,
create a perfectly blank slide (makes debugging easier) and insert a textbox
containing something.  Create an animation step that will Disappear the text
box on a mouse click.  Now run this code:

dim slidenums as new collection

For i = 1 To ActivePresentation.Slides.Count  
  For j = 1 To ActivePresentation.Slides(i).Shapes.Count
     If ActivePresentation.Slides(i).Shapes(j).AnimationSettings.Animate =
msoTrue Then
        slideNums.Add ActivePresentation.Slides(i).SlideNumber
        Exit For
     End If
  Next j  
Next i

' now display the slide numbers in a message box
If slideNums.Count = 0 Then
  MsgBox "No slides with animation found", vbOKOnly, "Animated Slides"
else
  ' i had some code here to display the slide numbers.  It's not germane.
end if

I get the "No slides ..." message in such cases.

Interestingly, if the Disappear is followed by an Appear, the code manages
to identify the slide.

So - is there a way to find such slides? How?  PowerPoint clearly knows how
to do it - how can I?