"tearing off" to me means creating a new window -- I don't know any terminal which lets you down a new window (although terminal lovers wouldn't want that I imagine).
Yes that's the idea. Tearing off a tab in vim and creating a new terminal window with an instance of vim having contents of that tab. This is possible in vim guis but afaik not in any terminal version.
When I'm using an IDE (vim-based or otherwise), I tend to have other things integrated into the editor session, for example I'm connected to a REPL or other external thing. If I pop a tab out into a new window, I don't want it to be an entirely separate editor session: I want it to keep all these extra integrated things as the parent. I still want to be able to evaluate code in the same REPL session as the parent without having to create a new session or connection.
I'm not sure how to handle something like this in a terminal editor, unless the vim plugins are aware of it (but they're not, since they weren't written for it). In a non-terminal editor like nvui, the new window could be just a view into a buffer, but still running inside the one instance of vim, allowing these plugins to keep working transparently, even though now there are multiple windows.
I don't think this is something that's easily possible with terminals without rewriting all the plugins that might need to be aware of it.
In ideal world: reordering, tearing off and merging.
> Which operations would you put under the menu?
Ostensibly, all of them?