The month view showed one month at a time and only the arrows moved it.
With the new "Free scrolling" setting (on by default, the webmail's
`calendarFreeScroll`) it is one continuous list of weeks, as in the
webmail (15a5497a, ae403b06):
- the month under the upper part of the grid is drawn at full strength,
names the title and is where the arrows step from; the first day of
each month carries the month's name
- reaching the top or the bottom adds weeks there and loads only their
events; weeks added above keep the rows on screen in place
- rows have a fixed height and snap to whole weeks, so the list stays
windowed and navigation lands exactly on the month
Turning the setting off brings back the paged month and a fixed 30-day
agenda. The week view still pages.