Can't set some properties in network shapes

[cnelson nycap rr com]

I'm using Dia 0.95-pre7 on 'Windows XP to create network diagrams to
include in a PowerPoint presentation.  It's great!  I'm deeply indebted
to the Dia developers and appreciate all they do.  But I have a small
problem.  For a series of slides I'm working on now, I want to have the
same diagram but deemphasize parts of it from slide to slide.  I thought
I'd start with a base drawing then change the color or transparency of
different objects but when I open the property sheet for the Network
Hub, there's a Fill Color that I can set but it seems to have no effect,
the hub remains gray.  The same is true of the general computer.  Am I
missing something or is the property broken?

                                          Chris