Hitting enter in autocomplete field doesn't work after typing component name with a space in it

In the CONFDEV project on JAC, we have a component 'The Muppets' for our team. The component autocomplete doesn't work very well for me because it has a problem with multiple words in the component.

The following breaks all the time for me in Firefox 3.6:

1. In the edit issue screen, click in the Component/s field
2. Type "The Mu"
3. The autocomplete shows my component, "The Muppets", and it is selected (see screenshot)
4. Hitting enter results in the error, "the mu is not a valid component" (see screenshot)

By contrast, if you don't type the second word at all, and just enter 'The', then the autocomplete works correctly.

At a guess, I'd say that either the space key handling in the autocomplete is doing something incorrect or the behaviour when hitting enter doesn't handle multiple words correctly.