shapes in presentation not updating

[Andy]

I have a powerpoint page that contains a set of command buttons and a set of rectangles. The buttons are used to turn the rectangles on and off to show different configurations of the data they represent.

Here is the code for one button:

Private Sub CommandButtonTRL1_Click()

ActivePresentation.Slides("Slide436").Shapes("FNC").Visible = msoFalse

ActivePresentation.Slides("Slide436").Shapes("RIF").Visible = msoFalse
ActivePresentation.Slides("Slide436").Shapes("SBIR").Visible = msoTrue
ActivePresentation.Slides("Slide436").Shapes("RTT").Visible = msoFalse
End Sub

the problem is, if you start the presentation with any rectangle off, it will not reappear while running the presentation. This would usually be because you closed it with the rectangle off. I have a macro that can be run while in "design" mode to make all the rectangles appear again but that involves the operator remembering to do that.
Is there a technical solution - preferably to make the rectangles appear in the presentation even if they were off to begin with.
I have tried changing the transparency and color and those don't work at all when the presentation is running.
I am using PowerPoint 2007 on Windows XP SP 3.