Ctrl semicolon behaves strangely

I can't bind anything to \`C-;\` because it acts like a strange compose key even though it's not a compose key. If I hit my compose key I have a normal behaviour wherever I am. If I hit \`C-;\` anywhere, nothing happens, but in emacs: ​ ​ https://preview.redd.it/7oacsm3a1rj91.png?width=128&format=png&auto=webp&s=e5ac5e767c5a2e26fb6d74c88204c8bedfb32986 And I can write anything I want, it will only close if I hit \`C-;\` again. ​ https://preview.redd.it/yf5hzlbm1rj91.png?width=185&format=png&auto=webp&s=f7a0b4ad92da29ed041724641c6446ff6599946b I've never had this behaviour before. I'm on emacs 29.0.50.

Not an Emacs thing, something at the DE/WM/OS level is intercepting the keystroke.

But why is it intercepting only when I'm using it in emacs then?

If your using gnome based distro, the following post might help. See the top voted comment. [https://www.reddit.com/r/emacs/comments/vkviqk/what\_is\_this\_overlay\_in\_ubuntu\_22\_emacsng\_when\_i/](https://www.reddit.com/r/emacs/comments/vkviqk/what_is_this_overlay_in_ubuntu_22_emacsng_when_i/)

Thanks a lot!