title: is ng-scope inserted only for new scopes?
body: <p>This may sound kinda dumb .. But I have problems understanding if the 'ng-scope' class is inserted only when a new scope is created, or is it something else ?</p>
  
  <p>Example : I have these lines of code linked to a controller : </p>
  
  <pre><code>&lt;button class="btn" ng-click="open()"&gt;Open me!&lt;/button&gt;
  &lt;div ng-show="selected"&gt;Selection from a modal: {{ selected }}&lt;/div&gt;
  </code></pre>
  
  <p>In the web console, both have an ng-scope : </p>
  
  <pre><code>&lt;button class="btn ng-scope" ng-click="open()"&gt;Open me!&lt;/button&gt;
  &lt;div ng-show="selected" class="ng-scope ng-binding ng-hide"&gt;Selection from a modal: &lt;/div&gt;
  </code></pre>
  
  <p>Even when there is no angular-specific data, like here, it will add an ng-scope :</p>
  
  <pre><code>&lt;div&gt;hello&lt;/div&gt;
  </code></pre>
  
  <p>outputs</p>
  
  <pre><code>&lt;div class="ng-scope"&gt;hello&lt;/div&gt;
  </code></pre>
  
  <p>But why ??</p>