colorbar() not working with scatter

Dear all, At the moment I'm heavily using the scatter plot

    > (great!). But if I want to add a color bar (with the
    > command colorbar(), directly following the call to
    > scatter) to explain the meaning of the colors of the
    > patches, matplotlib (0.64) refuses to make a colorbar with
    > the following message:

I Arnold, thanks for alerting me to this problem. This was a bug, and
is now fixed in CVS. I should be releasing a new version of
matplotlib next week which has these changes plus more.