title: Joomla 2.5 component: com_categories appear without toolbar buttons
body: <p>I developing some component for Joomla 2.5. I follow official tutorial:<br>
  <a href="http://docs.joomla.org/Developing_a_Model-View-Controller_Component/2.5/Adding_categories" rel="nofollow">http://docs.joomla.org/Developing_a_Model-View-Controller_Component/2.5/Adding_categories</a>  </p>
  
  <p>Now, I added categories functionality for my component, but when I open categories menu in administrative panel I don't see add, delete, edit buttons...<br>
  This is code of helper:</p>
  
  <pre><code>abstract class youtubeHelper
  {
          public static function addSubmenu($submenu) 
          {
                  JSubMenuHelper::addEntry(JText::_('COM_YOUTUBE_SUBMENU_ITEMS'),
                                           'index.php?option=com_youtube', $submenu == 'items');
                  JSubMenuHelper::addEntry(JText::_('COM_YOUTUBE_SUBMENU_CATEGORIES'),
                                           'index.php?option=com_categories&amp;view=categories&amp;extension=com_youtube',
                                           $submenu == 'categories');
  
                  // set some global property
                  $document = JFactory::getDocument();
                  $document-&gt;addStyleDeclaration('.icon-48-youtube ' .
                                                 '{background-image: url(../media/com_youtube/images/tux-48x48.png);}');
  
                  if ($submenu == 'categories') 
                  {
                          $document-&gt;setTitle(JText::_('COM_YOUTUBE_ADMINISTRATION_CATEGORIES'));
                  }
          }
  }
  </code></pre>
  
  <p>What I need do for add the buttons?</p>