Changed event name adminhtml_block_widget_tabs_html_before, add 'bl…

…ock' for name consistency. (#1358)

* Add a new event 'adminhtml_widget_tabs_html_before' for adding custom tab.

* Chaanged event name, added block in event 'adminhtml_block_widget_tabs_html_before' for consistency.

app/code/core/Mage/Adminhtml/Block/Widget/Tabs.php

@@ -189,6 +189,7 @@ protected function _setActiveTab($tabId)
 
     protected function _beforeToHtml()
     {
+        Mage::dispatchEvent('adminhtml_block_widget_tabs_html_before', array('block' => $this));
         if ($activeTab = $this->getRequest()->getParam('active_tab')) {
             $this->setActiveTab($activeTab);
         } elseif ($activeTabId = Mage::getSingleton('admin/session')->getActiveTabId()) {