Sub showHidden()
'NOTE this is ONLY for use in show mode
'NOTE the shapes will be visible when you finish the presentation
'The second code block fixes this it will run automatically
Dim osld As Slide
Dim oshp As Shape
Set osld = SlideShowWindows(1).View.Slide
For Each oshp In osld.Shapes
If oshp.Visible = False Then
oshp.Visible = True
osld.Tags.Add "TARGET", "YES"
oshp.Tags.Add "VIS", "NO"
End If
Next oshp
End Sub

Sub OnSlideShowTerminate(SW as SlideShowWindow)
Dim osld As Slide
Dim oshp As Shape
For Each osld In ActivePresentation.Slides
If osld.Tags("TARGET") = "YES" Then
For Each oshp In osld.Shapes
If oshp.Tags("VIS") = "NO" Then oshp.Visible = False
Next oshp
End If
Next osld
End Sub