I think they execute in the order they were initialized, although that's probably not good to rely on.

In this diff, it's OK if they run out of order because all show-more does is install a listener, and doesn't actually do anything interesting. So it could only error if an event fired between the listener being installed and the populate behavior running, which isn't possible today and is vanishingly unlikely to be possible even in some future world where the rules change, since you'd have to click really really fast. (In most cases, behavior-populate has to run before the links even appear on the page in order to fire the event.)

And, yeah, mooted by the next change.

Adding the "ChangesetDetailView" below makes the diff render with a header. Since we don't set a name, it uses a default name like /left/diff or something though if we don't make this change. It seemed reasonable to just use the page title instead of adding an option to hide the name.

(We don't show the "View Options" menu right now, but I'd like to at some point, and it would look really awkward if we hid the name since it would sort of just be floating there.)