Drupal 7

Related to my fieldset summary problem: autocomplete fields do not trigger the change event in Javascript, for some reason. I wound up stealing part of a patch I found somewhere (I would link to it if I could find it in my browser history) in order to override the autocomplete prototype function and trigger a new autocompleteSelect event when the user chooses an item in an autocomplete field. Just drop this function into a Javascript file in your module or theme:

Please excuse the long title: it took me a while to figure this one out, so I want to make sure that other people can find this when they need it.

On my current project, I'm changing the node author field based on the value of a user reference field on the node type: when a content admin sets the node reference field, the node author field is changed to match that user reference field value. Since the author field is shown in a fieldset, I wanted the summary on that fieldset to update when this change was made. It took me a while to figure out how, but it's pretty simple:

// Update the field summary if vertical tabs are in use
var tab = $('fieldset.node-form-author', context).data('verticalTab');
if (tab) {
  tab.updateSummary();
}