title: How to get checkbox in grid widgetcolumn from cellclick?
body: <p>My checkbox column:</p>
  
  <pre><code>{
     xtype: 'widgetcolumn',
     text: 'Selection',
     tdCls: 'actions',
     header: 'Selection',
     width: '5%',
     dataIndex: 'selection',
     widget: {
        xtype: 'checkbox',
        defaultBindProperty: 'disabled',
        listeners: {
           afterrender: function (chb) {
              var rec = chb.getWidgetRecord();
              chb.setValue(rec.get('selection'));
              chb.on('change', this.checkHandler);
              chb.setDisabled(rec.get('selection_disabled'));
           },
           scope: this
        }
     }
  }
  </code></pre>
  
  <p>How get checkbox in cellclick grid event for set value proggramatically? In cellclick me need change value of checkbox(<code>cbox.setValue(!cbox.getValue());</code> or the same).</p>