Index: blocks/navigation/renderer.php
===================================================================
--- blocks/navigation/renderer.php	(revision 7)
+++ blocks/navigation/renderer.php	(working copy)
@@ -1,7 +1,7 @@
 <?php
 
 class block_navigation_renderer extends plugin_renderer_base {
-    
+
     public function navigation_tree(global_navigation $navigation, $expansionlimit, array $options = array()) {
         $navigation->add_class('navigation_node');
         $content = $this->navigation_node(array($navigation), array('class'=>'block_tree list'), $expansionlimit, $options);
@@ -52,7 +52,6 @@
                 $attributes['class'] = 'dimmed_text';
             }
             if (is_string($item->action) || empty($item->action) || ($item->type === navigation_node::TYPE_CATEGORY && empty($options['linkcategories']))) {
-                $attributes['tabindex'] = '0'; //add tab support to span but still maintain character stream sequence.
                 $content = html_writer::tag('span', $content, $attributes);
             } else if ($item->action instanceof action_link) {
                 //TODO: to be replaced with something else
Index: lib/outputrenderers.php
===================================================================
--- lib/outputrenderers.php	(revision 7)
+++ lib/outputrenderers.php	(working copy)
@@ -2335,7 +2335,7 @@
             $content = $icon.$content; // use CSS for spacing of icons
         }
         if ($item->helpbutton !== null) {
-            $content = trim($item->helpbutton).html_writer::tag('span', $content, array('class'=>'clearhelpbutton', 'tabindex'=>'0'));
+            $content = trim($item->helpbutton).html_writer::tag('span', $content, array('class'=>'clearhelpbutton'));
         }
         if ($content === '') {
             return '';
@@ -2358,7 +2358,7 @@
             $content = html_writer::link($item->action, $content, $attributes);
 
         } else if (is_string($item->action) || empty($item->action)) {
-            $attributes = array('tabindex'=>'0'); //add tab support to span but still maintain character stream sequence.
+            $attributes = array();
             if ($title !== '') {
                 $attributes['title'] = $title;
             }