studio - tweaking problem editor's advanced editor toggle control UI and prompt message

cms/templates/widgets/problem-edit.html

@@ -16,7 +16,7 @@
                         class="problem-editor-icon dropdown"></span></a></li>
             </ul>
             <ul class="editor-tabs">
-                <li><a href="#" class="xml-tab tab" data-tab="xml">Use Advanced Editor</a></li>
+                <li><a href="#" class="xml-tab tab advanced-toggle" data-tab="xml">Advanced Editor</a></li>
                 <li><a href="#" class="cheatsheet-toggle" data-tooltip="Toggle Cheatsheet">?</a></li>
             </ul>
         </div>

common/lib/xmodule/xmodule/css/problem/edit.scss

@@ -45,11 +45,32 @@
       }
     }
 
+    .advanced-toggle {
+      @include white-button;
+      height: auto;
+      margin-top: -1px;
+      padding: 3px 9px;
+      font-size: 12px;
+
+      &.current {
+        border: 1px solid $lightGrey !important;
+        border-radius: 3px !important;
+        background: $lightGrey !important;
+        color: $darkGrey !important;
+        pointer-events: none;
+        cursor: none;
+        
+        &:hover {
+          box-shadow: 0 0 0 0 !important;
+        }
+      }
+    }
+
     .cheatsheet-toggle {
       width: 21px;
       height: 21px;
       padding: 0;
-      margin: 3px 5px 0 16px;
+      margin: 0 5px 0 15px;
       border-radius: 22px;
       border: 1px solid #a5aaaf;
       background: #e5ecf3;

common/lib/xmodule/xmodule/js/src/problem/edit.coffee

@@ -59,7 +59,7 @@ class @MarkdownEditingDescriptor extends XModule.Descriptor
   ###
   confirmConversionToXml: ->
     # TODO: use something besides a JavaScript confirm dialog?
-    return confirm("If you convert to the XML source representation, which is used by the Advanced Editor, you cannot go back to using the Simple Editor.\n\nProceed with conversion to XML?")
+    return confirm("If you use the Advanced Editor, this problem will be converted to XML and you will not be able to return to the Simple Editor Interface.\n\nProceed to the Advanced Editor and convert this problem to XML?")
 
   ###
   Event listener for toolbar buttons (only possible when markdown editor is visible).