I thought of that partly because my terminal can do that with its tabs, urxvt. Though it's not the same thing probably. But I know that nano has mouse support,

I thought of that partly because my terminal can do that with its tabs, urxvt. Though it's not the same thing probably. But I know that nano has mouse support, which I have enabled. 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.