I have several computers running xubuntu; my main PC does accented chars which is documented, an old 32-but Asus EEE produces a back-tick as it should, but my 64-bit EEE immediately closes the current tab in Terminal (specifically, xfce4-terminal) when I press the key. It doesn't close an untabbed Terminal.
Shift-backtick gets me a '¬' character, ctrl & alt modifiers do nothing, but just touching the key alone (or with Fn) closes my terminal. I've tried it with the 105-key Int'l layout, with the Asus-laptop layout; there are no compose settings,
setxkbmap says "rules: evdev, model: asus_laptop, layout: gb" which is as it should be.
This behaviour has survived a long time & a lot of updates - possibly even a reinstall (retained /home/), although I wouldn't swear to that.
There are no logs created (that I can see) when this happens, and it doesn't append the current history to ~/.bash_history.
Any ideas what this is doing, and how I can persuade it not to?