Click... in the VTY? I understand this is possible, I just did not realize people relied the functionality—it’s so easy to internalize truths like “people use the terminal to avoid using the mouse”.
Also works in tmux - you can drag your splits to resize them, or select a tmux "tab" to switch to it. You can also select text and then do things with it, like search back in the scrollback for other occurrences, or copy it to the system clipboard. Right click even brings up an in-cli context menu.
But it was more to describe real tabs. I don't see them in nano, just a bar at the top with "[1/n] filename", and no tabs. Searching for nano and tabs does not help of course, and I saw nothing in the manpage. So it was a try to describe the kind of tabs geany has.