tooltips for View and Insert menus

IPython/html/templates/notebook.html

@@ -106,14 +106,22 @@ class="notebook_app"
         </li>
         <li class="dropdown"><a href="#" class="dropdown-toggle" data-toggle="dropdown">View</a>
             <ul class="dropdown-menu">
-                <li id="toggle_header"><a href="#">Toggle Header</a></li>
-                <li id="toggle_toolbar"><a href="#">Toggle Toolbar</a></li>
+                <li id="toggle_header"
+                    title="Show/Hide the IPython Notebook logo and notebook title (above menu bar)">
+                    <a href="#">Toggle Header</a></li>
+                <li id="toggle_toolbar"
+                    title="Show/Hide the action icons (below menu bar)">
+                    <a href="#">Toggle Toolbar</a></li>
             </ul>
         </li>
         <li class="dropdown"><a href="#" class="dropdown-toggle" data-toggle="dropdown">Insert</a>
             <ul class="dropdown-menu">
-                <li id="insert_cell_above"><a href="#">Insert Cell Above</a></li>
-                <li id="insert_cell_below"><a href="#">Insert Cell Below</a></li>
+                <li id="insert_cell_above"
+                    title="Insert an empty Code cell above the currently active cell">
+                    <a href="#">Insert Cell Above</a></li>
+                <li id="insert_cell_below"
+                    title="Insert an empty Code cell below the currently active cell">
+                    <a href="#">Insert Cell Below</a></li>
             </ul>
         </li>
         <li class="dropdown"><a href="#" class="dropdown-toggle" data-toggle="dropdown">Cell</a>