Plugin no longer being processed

I wrote a plugin for tinymce in WYSIWYG and when I updated to 5.x-2.0 (from 5.x-1.3) the plugin no longer gets added. Is there documentation of what changed for writing a plugin to make it get added?

I can see it in the settings - but it looks like it's never coming back from the call to wysiwyg_get_all_plugins() into the loop that adds Drupal plugins even though its hook_wysiwyg_plugin is being hit. Break is the only plugin that's coming through in that loop from what I can tell.

Here's the code for the hook

/**
 * Implementation of hook_wysiwyg_plugin().
 */
function tinymce_footnotes_wysiwyg_plugin($editor) {
  switch ($editor) {
    case 'tinymce':
        return array(
          'tinymce_footnotes' => array(
            'type' => 'external',
            'title' => 'Footnotes',
            'description' => 'Add footnotes via a popup',
            'path' => drupal_get_path('module', 'tinymce_footnotes') .'/tinymce_plugin',
            'icon' => array('tinymce_footnotes' => t('Add Footnotes')),
            'buttons' => array('tinymce_footnotes' => t('Add Footnotes')),
            'url' => 'http://drupal.org/project/footnotes',
            'extended_valid_elements' => array('fn'),
            'basePath' => base_path(),
            'settings' => array(),
          ),
        );
    break;
  }
}