Multi-window mode allows the user to create side-by-side comparative displays. Blah, blah, blah.
Sketch: Here's a picture of what a side-by-side month display looks like.
Figure 44: Side-by-side monthly display.
This is created by turning on multi-window mode, executing `View Month' three
times, and moving the resulting output windows next to each other. We may want
to consider a form of window "magnetization", as in Adobe tools, where windows
snap up to each other when they're moved in close proximity.