Maybe can add Invisible calendars options in Skin Filter function ,like categories filter.
If users need add or delete calendar frequently ,it's a little inconvenient to set skin filter again if have public calendar (e.g. holiday calendar) not want show in the skin.

I'm not following you. You can already define which calendars are shown in a window. How would this be different?

For example:
I have calendar files name "Note" "Work" "Holiday"
I set "Note" ,"Work" for events list as visible calendars just to exclude "Holiday"
But now somebody give me his calendar name "Co-work" , I add it and need to go to skin option to set "Note" ,"Work" ,"Co-work" as visible calendars again to show "Co-work" in windows.
If just set "Holiday" as Invisible , it does not need to set filter again.

Alright, if this is no different, I'll not expect this function.
I'm so sorry for bothering you again.

No need to apologize. Your suggestion was good but I just didn't understand it. I'll add the feature to my backlog.

THX!
Maybe my poor English cause the misunderstand.
Thanks again.