widget locking

When I run the following: figure(); plot([1,2]) figure();

    > plot([1,2])

    > and then I use the zoom widget in one figure, and then try
    > to use the zoom widget in the other figure without turning
    > off the first zoom widget, I get an error. Is this
    > desirable?

No -- I hadn't considered this use case. The locking should be on a
per figure basis. I introduced locking to handle the case where
someone wants to use a widget that draws onto the canvas (like the
lasso tool) w/o interfering with the other tools that are handling
events. Eg, if pan/zoom is enabled and you are also trying to draw a
lasso, all hell breaks loose.

I've commented this out and will re-implement after further
consideration. Thanks for the heads-up.