title: When you double-click on the widget is thrown
body: <h1>When I do double-click on the widget is thrown:</h1>
  
  <blockquote>
    <p>Uncaught TypeError: Cannot read property 'focusable' of undefined</p>
  </blockquote>
  
  <p><p>I have grid with widget column
  <p></p>
  
  <pre><code>text:'blabala'
  flex: 1.8,
  xtype: 'widgetcolumn',
  dataIndex: 'attachment',
  stopSelection: false,
  
  widget: {
              xtype: 'panel',
              layout: 'hbox',
              padding: 5,
              border: 0,
              bodyStyle: 'background:transparent',
              flex: 1,
              header: false,
              items: [{
                  xtype: 'panel',
                  flex: 1,
                  bodyStyle: 'background:#d7d7d7;border-radius:16px',
                  layout: 'hbox',
                  items: [
  
                      {
                          xtype: 'button',
                          cls: 'attach-btn-divers',
                          padding: '10 0 10 5',
                          textAlign: 'left',
                          flex: 1,
                      }, {
                          xtype: 'button',
                          cls: 'attach-btn-divers attach-btn-divers-cancel',
                          padding: '10 5 10 0',
                          iconCls: 'x-fa fa-close',
                          handler: 'onDetachDiver',
                          width: 20,
                      },
                  ]
              }, {
                  xtype: 'combolabel',
                  forceSelection: true,
                  store: {
                      type: 'divingAttachmentStore'
                  },
                  displayField: 'value',
                  valueField: 'value',
                  autoSelect: true,
                  queryCaching: false,
                  queryMode: 'remote',
  
                  listConfig: {
                      loadMask: false
                  },
                  flex: 1,
                  listeners: {
                      specialkey: 'onEditAttachment',
                      focusLeave: 'onFocusLeaveAttachment',
                      beforequery: 'onBeforeQueryAttachment'
                  }
              },
              ]
  
          },
          onWidgetAttach: 'onWidgetAttachAttachment',
  </code></pre>
  
  <p><p> When editing, combos are displayed
  <p> In the normal view, a panel with buttons is displayed
  <p> if empty cell, then combos are displayed with empty text. When you click on the combo, a list drops but with an error</p>
  
  <h1>Update 29.03.2017</h1>
  
  <p>If the edit plugin is removed, then there is no error.
  Reproduced:
  <a href="https://fiddle.sencha.com/#view/editor&amp;fiddle/1t1v" rel="nofollow noreferrer">https://fiddle.sencha.com/#view/editor&amp;fiddle/1t1v</a>  </p>