Apple Calendar has a 'tab bar'. How do you use it?

Question

I just realised Apple calendar on macOS has a tab bar, which can be toggled from the menu via View ► Show Tab Bar.

What is this for, and how do you create a new tab? I imagine it's to have two or more calendars in separate views; or maybe to have different time views (Monthly/weekly)

Does anybody know how to use this part of the calendar app?

Answer 1

How to use:

• turn on Tab Bar,
• on Menu Bar > Window, at the bottom there should be calendar(s) name(s)
• clicking on calendar name opens it in new window (now there are two Calendar windows)
• drag-and-drop name/tab on Tab Bar from one Calendar window to another. You can drop it while hovering over Tab Bar when it becomes Tab Bar wide
• second window disappears and there is only one Calendar window with two tabs

I have no idea what calendar(s) and based on what appear in Window menu.

Answer 2

It (supposedly) lets you view external calendars, but not multiple local or iCloud ones.

Answer 3

It not only opens the calendar in a new tab, but duplicates it. And it again downloads all the events that it has previously downloading. It's a strage behaviour.