When selecting the calendar tab, the browser becomes unresponsive. Only about 40 seconds later, the calendar finally loads. I used the calendar previously and I don’t remember it being that bad.
Taking a quick peek with the Firefox dev tools, Firefox gets completely locked up after a second or so, only does GC for about 40 seconds, and then recovers.
I’ve tested this again on a new profile (should have done that in the first place). It still happens, although it only takes 35 seconds on a new profile until all calendars & appointments are loaded.
Thanks both for you comment on this issue. I wonder if this has anything to do with the number of items in the calendar? We are aware of some issues, but 40s is quite excessive.