First of all using "pre" makes me frustrated. Usually you would use it to copy/paste code or configuration snippets into a discussion. However it doesn't work as expected. It creates a new "box" for every line. Try it out!
However, trying it out more than once will prove difficult because when you go to the "preview" tab and then return to the "compose" tab will totally garble the text you just wrote with HTML artifacts....
(It's always frustrating when even the most basic things don't work.)