Форум поддержки Thunderbird

Dear all, is there an option to have Thunderbird sync network calendars once upon start? I have a couple of large network calendars and repetitive syncing causes performance problems, but on the other hand, if I set sync to Manual, Thurderbird does not sync upon start and shows only the events that had been cached locally (off-line) in the past, but not any events meanwhile added to the network calendar by other clients. Thus, I either have to remember to manually sync once every calendar after each program start, or I have to activet syncing every xx minutes, which causes the programm to periodically freeze for some time (during syncing). Is there any good solution to this? Is there maybe an option in the config editor "sync upon start"? Thank you very much.

Dear all, I have a couple of calendars on the disk as network calendars (file:///...ics) with offline support, and I just realized that I cannot delete any event. These calendars are not read-only, I can see the option delete, both with right-click on the event and double-click to edit the event, but after pressing delete, the event remains on the calendar. Just pressing the delete button on the keyboard after selecting the event has the same behaviour. If I try shift the events from one calendar to the other, they do appear in the new calendar, but they do not disappear from the old. I have restarted Thunderbird, and also tried this on another computer with the same results. Both szstems are Windows 11, Th underbird 115.10.1 I would be very grateful for any suggestions