calendar legend too long with multiple terms

If you use the current multi-term sample data, a teacher sees every instance of each section he's taught in the default calendar legend. So in the sample case, this is 18 calendars, many of which will have the same name. Too much.

A general fix seems to be to make the legend based on the calendars which actually have events for that day. The tricky part would seem to be that you have to be able to uncheck a calendar in your legend list if you don't always want to see it, but it should appear (unchecked) in the legend if there is an (invisible) event for that day, so you know you can turn it and see something. Perhaps also some kind of "show all" option is necessary for similar cases where you need to see what you have turned on and off globally.