Hierarchical Select No Longer Creates Additional Select Boxes

Ok, I have updated to the dev module. This has fixed the taxonomy page issue, however I am still having the same issue with the genre field I have added to books. It will not create the second box when a top level item is created. I thought it might be a JS conflict, however the second box is now created perfectly on the form when adding a new taxonomy term, so I guess it can't be a JS conflict.

Here is my exported config:

$config = array(
  'config_id'       => 'taxonomy-17',
  'save_lineage'    => 0,
  'enforce_deepest' => 1,
  'entity_count'    => 0,
  'require_entity'  => 0,
  'resizable'       => 1,
  'level_labels' => array(
    'status' => 0,
    'labels' => array(
      0 => '',
      1 => '',
    ),
  ),
  'dropbox' => array(
    'status'    => 1,
    'title'     => 'All selections',
    'limit'     => 0,
    'reset_hs'  => 1,
  ),
  'editability' => array(
    'status' => 0,
    'item_types' => array(
      0 => '',
      1 => '',
    ),
    'allowed_levels' => array(
      0 => 1,
      1 => 1,
    ),
    'allow_new_levels' => 0,
    'max_levels'       => 1,
  ),
);

Ok, I've done some playing/testing - here are my findings:

1. With JS disabled, the second box does indeed appear by using the 'update' button. However the add button does not work, and it becomes impossible to add genres at all.

2. With JS enabled, I used Chrome to edit the properties of the update button and removed the display: none; property. By doing so, I was able to use the update button on the top level items. This spawns the second box! It also allows me to add genres normally... so it seems that there is something gone awry, although I cannot say what at this time.

Obviously refreshing the page hides the update button again, so this is no permanent fix, however it seems that the JS script is not starting the 'onclick' trigger for the top level item box correctly to me, since forcing the function with the update button does work.

Thoughts?