When I type
ctrl-; in Gnome Terminal, it prints an underlined letter e. If I type a bunch of letters, they're also underlined. When I hit enter, the underline goes away, and the first e also goes away. What is it doing?
(graphical) Emacs does almost the same thing. When I type
ctrl-;, Emacs shows a graphical overlay (that doesn't look like Emacs) with the letter e. Typing letters adds to this overlay, and when I hit enter, the letters (except the e) get put into the Emacs buffer.
This doesn't happen on my other laptop that's running Ubuntu. This one is running Fedora 36.
If I try the above with xterm, I get the overlay like I do in Emacs. If I change focus to another window without hitting enter, whatever was underlined disappears.