Vista - Heavy memory usage in WPF application ?

I have a UI which basically creates lots of styled buttons (perhaps 200+)
which are all instantiated but not all Visible at any time.

When I run my app and try and step through it there is one final step that
happens after all my code has apparently executed but before the UI actually
appears on screen.
As I can't step thru this part of the execution I don't know what is
happening.

During this step
- the machine goes to 100% CPU usage for about 10 seconds
- the TaskManager shows me that the memory footprint of the app has gone
from approx 40MB to > 400MB

(This is running within VS2005, by the way - Outside VS2005 the increase is
similar but the start and end figures are 25-30MB lower.)

After that it is not too punchy (sometimes it seems like 0.5 seconds between
a click and a button responding).


I have no way to know if this is normal. It seems a pretty outrageous
figure for a program with very little in the way of data structures in it.

Is there any way I can step through where it is happening and see what
exactly is consuming so much mem ?


--
Griff

Beta 2 WPF, XP SP2, VS2005
2GB Ram and 3.2 GHz main CPU,
Asus EAX 300 Se Graphics adapter


(trying to make an industrial UI with XAML/WPF/c#)