Ubuntu Linux 10.04, matplotlib version: 0.99.1.1, backend GtkAgg;
probably the same in all later versions

There seems to be no way of protecting a GUI-only figure containing
matplotlib widgets. If this figure becomes active, any pyplot command
will draw over the widgets. As an example, this happens in the built-in
subplot_tool function where the plot command draws into the Reset box:

$ ipython -pylab
In [1]: subplot_tool()
# click any slider
In [2]: plot(range(2))

MATLAB deals with this issue by having a HandleVisibility and IntegerHandle
properties, which prevent a GUI figure from becoming the active one and protect
it from accidental changes. It would be surely useful to have some similar
option of protecting GUI figures in matplotlib.