Undefined index errors using 'Select (or other) drag and drop lists'

After applying your change in #5 an error still occurred so I changed the start of the function from:

/**
 * Element validate callback for a Select (or other) field widget.
 */
function select_or_other_field_widget_validate($element, &$form_state) {
  $field_info = field_info_field($element['#field_name']);
  ...

to:

/**
 * Element validate callback for a Select (or other) field widget.
 */
function select_or_other_field_widget_validate($element, &$form_state) {
  $field_name = $element['#parents'][0];
  $field_info = field_info_field($field_name);
  ...

Then your:

  $instance = $form_state['field'][$element['#parents'][0]][$element['#parents'][1]]['instance'];

can become:

  $instance = $form_state['field'][$field_name][$element['#parents'][1]]['instance'];

which looks nicer. But about this:

and doesn't fix the ordering issue

If you mean the checkbox "Sort options - Sorts the options in the list alphabetically." I checked that and it appears to sort the select list on the content type creation form. So yeah - maybe that's working? Am I supposed to be seeing a plain old select list there, though? Or a list of drag and drop items... because it's just a plain select list. But it sorts alphabetically (by value) when the checkbox is checked, and doesn't sort when the checkbox is unchecked. Which is good.

It would help to update the description "Sorts the options in the list alphabetically." to "Sorts the options in the list alphabetically by value." just to make this clear to an administrator before they select it.

Alphabetical... natural order... I only suggested adding "by value" to the description. It's not my writing otherwise.

It would be helpful to indicate sorting applies to values, and not keys. Rather than not indicating either way.

Patch attached contains the fix, and the 'Sort options' elaboration on sorting by value.

Windows patching: http://drupal.org/node/620014
Mac OS X patching: http://drupal.org/node/60818

Because the "patch" command is a Unix command—not a Drupal command or a Windows command—Windows users need to utilize a tool that allows them to run Unix commands.

So... once the "patch" command is operational for you, type "patch --help". That will list some very helpful examples.

@danielb - for future reference, under a user's profile you'll find an instruction on how to pass authorship attribution to that user, via 'git commit'.

A number of patches you've applied in the past could have had authorship attributed to other users. If you fail to do this in future, authorship of patches will continue to be attributed to yourself! :-)