hidden calendars: keep shared calendars in their place

[stefangweichinger]

Is your feature request related to a problem? Please describe.

coming from #6259:

my customer reports irritated users after upgrading from NC-29.08 to 30.01 today.

they have dozens of calendars shared and are used to toggle the visibility very often in their usual workflows, without the hidden calendars "disappearing" into a separate section all the time.

Describe the solution you'd like

They ask for the old behavior or some option to have 3 states like

• on
• off temporary ("I want to see only the other calendars for a second, but re-enable the calendar's view asap")
• hidden: I subscribe to a calendar, but normally I don't look at it. Maybe only once a year or so ...

But at first: let the shared calendar in place but let us only toggle it on/off (as earlier)

thanks!

Describe alternatives you've considered

No response

Additional context

No response