Gee, I'm starting to get the feeling your the first person
> who's every actually *used* matplotlib 
No, but maybe you're the only one who is stress-testing CVS 
This is another CVS bug, introduced when I let the figure store it's
canvas, in response to a request by ChrisBarker to be able to do
fig.savefig('blah)
which forwards the call on to the canvas.
I was failing to reset the canvas instance for a given figure after a
call to switch_backends (which is what happens when you save a ps fig
from agg).
This is (should be) fixed in CVS.
JDH