I've just tried the Qt4 backend and noticed that, different from the
previous backend I was using, the last command of a script pylab.show()
does not raise the figures to the front (they show up but in the
background). This is the case at least on my OS X machine. I personally
feels like the figures taking becoming the active windows should be the
right behavior. In case, this is valuable to the project, please find
below at patch that achieves that behavior.