I agree @ block commenting - would be a nice little tweak.
Another UI feature I miss would be a pull down menu listing functions - in order to be able to jump to a particular function instead of having to scroll around.
That might be beyond the bare bones aspect of the IDE and is available through using an external editor like BBEdit (on Mac) but BBEdit doesn't do formatting so I am torn between features.
The block commenting and indent / de-indent would definitely be great. Do you guys want to suggest it on the Processing forum / bugs list? Then I can port the implementation over from there.
Or does Processing already do that? (In which case, I'll try to get it into Arduino ASAP.)