If a term doesn't have children the option "<create new>" is displayed, no matter if "Allow creation of new terms" is selected

This is caused because a missing Parenthesis in "OR" condition in line 1470 of hierarchical_select.module

Currently:

 if ($config['editability']['status']
      && $config['editability']['allow_new_levels']
      && $config['editability']['max_levels'] == 0 || count($hierarchy->lineage) < $config['editability']['max_levels']
      && module_invoke($config['module'], 'hierarchical_select_valid_item', end($hierarchy->lineage), $config['params'])
      && module_hook($config['module'], 'hierarchical_select_create_item'))
  {

It should be:

  if ($config['editability']['status']
      && $config['editability']['allow_new_levels']
      && ($config['editability']['max_levels'] == 0 || count($hierarchy->lineage) < $config['editability']['max_levels'])
      && module_invoke($config['module'], 'hierarchical_select_valid_item', end($hierarchy->lineage), $config['params'])
      && module_hook($config['module'], 'hierarchical_select_create_item'))
  {

patch attached.