Typing lower case x in a terminal window opens a new terminal window

[Chris Jones]

I am running Fedora 14, and now when I open a terminal window and type 
any command, as soon as I type a lower-case x character, a new terminal 
window opens and control is passed to it.

How do I change this annoying behaviour to what I would expect? If I put 
the Caps Lock on and then type Shift-x, I do get the lower-case x 
without the new terminal window being opened.