How do I prevent xfce terminal from grabbing the Alt key?

[Chris G]

How can I stop xfce terminal (i.e. xfce4-terminal) from grabbing the Alt
key for its own purposes?

I want my Alt key to act as a shift key and allow me to type things like
accented characters easily rather than do the very odd things it does by
default in an xfce terminal.  

I think it's *trying* to change tabs but since I virtually never use
tabs in my terminals that's totally redundant.  What it actually does is
nothing at all with most keys on the keyboard and shows "(arg: n)" with
numeric keys.  xfce terminal doesn't just steal the alt+n keys though,
it prevents Alt working at all.

-- 
Chris Green