Drupal's attach behaviours : react on all newly loaded content?
This, from the comments in misc/drupal.js, explains how it's supposed to work:


Drupal.attachBehaviors is added below to the jQuery ready event and so
runs on initial page load. Developers implementing AHAH/Ajax in their
solutions should also call this function after new page content has been
loaded, feeding in an element to be processed, in order to attach all
behaviors to the new content.