title: extjs 4.1: Fix width of collapsible panels in table layout
body: <p>I am working on ExtJs collapsible panel in table layout.
  Whenever I open the page the panel comes up perfectly fine (width wise).
  Please check the below images
  <img src="https://i.stack.imgur.com/X0jzw.png" alt="Full application screen">
  <img src="https://i.stack.imgur.com/mTORz.png" alt="Panel causing problem"></p>
  
  <p>But when I collapse the panel, the width changes! 
  See the below image:
  <img src="https://i.stack.imgur.com/h3XwA.png" alt="Collapsed panel"></p>
  
  <p>A sample code to replicate this issue:</p>
  
  <pre><code>Ext.create('Ext.panel.Panel', {
  title: 'Car Simple Tree',
  renderTo: Ext.getBody(),
  layout: {
      type: 'table',
      columns: 2
  },
  items: [{
      xtype: 'panel',
      title: 'panel title',
      collapsible: true,
      titleCollapse: true,
      bodyStyle: {
          background: '#D9E5F3',
          borderColor: '#99BCE8',
          borderWidth: '1px'
      },
      scrollable: true,
      autoScroll: true,
      layout: {
          pack: 'center',
          type: 'hbox'
      },
      rowspan: 1,
      colspan: 2,
      width: '100%',
      items: [{
          text: 'Save',
          xtype: 'button',
          padding: 5
      }]
  }, {
      html: 'Cell C content',
      cellCls: 'highlight'
  }, {
      html: 'Cell D content'
  }]
  });
  </code></pre>
  
  <p>I have also created a fiddle with the same code.
  <a href="http://jsfiddle.net/ATechieDiary/8MjZa/" rel="nofollow noreferrer">JSFiddle Demo</a></p>
  
  <p>Please help me in resolving this issue. 
  I want the width of the panel to remain fixed whether it is collapsed or not.
  But I <strong>WANT</strong> to set width in the terms of percentage and not fixed absolute number.</p>