Sidebar's calendars list popup can make it difficult to distinguish some calendars
On my calendar, I have two accounts, and the popup in the calendar that allows enabling/disabling calendars is very cramped. Furthermore, knowing which calendar belongs to which account is tough****. Look for example in the following screenshot:
The calendar above shows two copies with similar names for "Holidays in Rwanda" and "Birthdays". It is tough to know to which account each calendar belongs.
I think the solution would be to show sections in the popover for each account. A separator can separate each section to show they are from a singular account, and each section may have a title corresponding to the calendar name.