title: ExtJs 4 reference to toolbar button in grid
body: <p>i want to define a ref inside the controller to enable/disable the delete buitton on selection change. But i don't get it right, so the getDelButton()-Method delivers undefined. PLease help...</p>
  
  <p>Controller:</p>
  
  <pre><code> refs:[
        { ref: 'tabPanel', selector: 'viewport &gt; tabPanel' },
        { ref: 'grid', selector: 'tabPanel &gt; usermanagementgrid' },
        { ref: 'delButton', selector: 'grid &gt; button #delete'}
  ],
  </code></pre>
  
  <p>...</p>
  
  <pre><code>this.getDelButton().setDisabled(false);
  </code></pre>
  
  <p>View definition:</p>
  
  <pre><code>dockedItems: [{
          xtype: 'toolbar',
          items : [ {
              xtype: 'button',
              id: 'delete',
              iconCls: 'drop-add',
              text: 'Add',
              tooltip: 'Press to add a new user.',
              action: 'addUser',
              scope: this,
          },
  </code></pre>
  
  <p>Thanks in advance...</p>