and find the following [line 110 in J1.5.23]:
/* * Content SubMenu */Replace the block of menu code with :
/*
* K2 Content SubMenu
*/
$menu->addChild(new JMenuNode(JText::_('K2')), true);
$menu->addChild(new JMenuNode(JText::_('Dashboard'), 'index.php?option=com_k2', 'class:menu'));
$menu->addChild(new JMenuNode(JText::_('Article Items'), 'index.php?option=com_k2&view=items', 'class:article'));
$menu->addChild(new JMenuNode(JText::_('Article Categories'), 'index.php?option=com_k2&view=categories&filter_trash=0', 'class:category'));
$menu->addChild(new JMenuNode(JText::_('Article Tags'), 'index.php?option=com_k2&view=tags', 'class:tags'));
$menu->addChild(new JMenuNode(JText::_('Article Comments'), 'index.php?option=com_k2&view=comments', 'class:comments'));
$menu->addSeparator();
$menu->addChild(new JMenuNode(JText::_('Users'), 'index.php?option=com_k2&view=users', 'class:user'));
$menu->addChild(new JMenuNode(JText::_('User Groups'), 'index.php?option=com_k2&view=userGroups', 'class:user'));
$menu->addSeparator();
$menu->addChild(new JMenuNode(JText::_('Extra Fields'), 'index.php?option=com_k2&view=extraFields', 'class:cpanel'));
$menu->addChild(new JMenuNode(JText::_('Extra Field Groups'), 'index.php?option=com_k2&view=extraFieldsGroups', 'class:cpanel'));
$menu->addSeparator();
$menu->addChild(new JMenuNode(JText::_('Trash'), 'index.php?option=com_k2&view=items&filter_trash=1', 'class:trash'));
$menu->getParent();
You'll now see the top bar main drop down menu with K2 specific items. 