[development] behaviors context

[Matt Farina]

> The problem occurs only when you assume the context is passing
> sufficient information for your behavior. The context may in fact be
> providing less information than you need, and you are at the liberty
> of whatever called attachBehavior() in the first place (which may not
> be something in core -- there's no way to tell). Consequently, it's
> better to rely on the document itself, not just the context.

Sometimes you can't just rely on the document. For an example see the  
popups module. It attaches the behaviors to the body of the popup  
window. If a popup is built from an AHAH callback you wouldn't want to  
reapply the behaviors to the entire document for a popup that's just  
part of it. You'd want to apply it to just the new area.

If someone misuses attachBehaviors() should the behaviors be required  
to deal with that? They can't foresee everything and there are times  
where you want to attach behaviors to something other than the  
document. If they misuse attachBehaviors that would be a bug in their  
code.