I have several calendar layers, some have about 10 calendars in them. Many of these calendars always have projects in them, but others have projects only occasionally. So, the calendars that are blank end up taking some space on the screen, but only show that there are no projects / tasks in them (see attached image). This is good for seeing which calendars have tasks and which do not, but not as good for processing all current projects.
It would be handy to have a toggle or check to show all calendars that are selected, or to show all selected calendars that also have projects/tasks in them (exclude those that are empty).