title: An accordion layout inside a tab, inside a border layout gives me slider bars when the region is resized. Only happens in Chrome.
body: <p>I'm getting started on Ext using Ext JS 4 and I'm running with a strange behavior on Google Chrome. 
  I have a viewport with a fit layout. Inside it, I have a panel with a border layout.
  It has a southern region, a western region, and a central region.
  The western region has a tabpanel, and inside the first tab I have an accordion panel.</p>
  
  <p>The problem is that when I collapse a panel, or reduce the size of the western region, in Chrome I get evil slider bars. On firefox it works just fine, it only happens in Chrome.
  It doesn't happen when I'm on the tab 2 (the one that doesn't have the accordion panel). 
  Any idea of what could be the problem? </p>
  
  <p>These are pictures depicting the problem: <a href="http://imgur.com/a/vgbcE" rel="nofollow">http://imgur.com/a/vgbcE</a><br>
  Here is the source code: </p>
  
  <pre><code>Ext.application({
      name: 'HelloExt',
      launch: function() 
      {
          var viewPort = Ext.create('Ext.container.Viewport', {
              layout: 'fit',
              renderTo: 'layout'
          });
  
          var mainLayout = Ext.create('Ext.panel.Panel', {
              width: 'auto',
              layout: 'border',
              title : 'Gis Web',
              collapasible: true,
              defaults: {
                  split: true,
                  border: false,
                  collapsible: true,
                  manageOverflow: 2
              },
              items: [
                  {
                      region: 'center',
                      collapsible: false,
                      id: 'center-panel',
                      border: true
                  },
                  {
                      id: 'south-panel',
                      region: 'south',
                      height: 100
                  },
                  {
                      id: 'west-panel',
                      region: 'west',
                      width: 200,
                      layout: 'fit'
                  }
              ]
          });
  
          var accordionPanel = Ext.create('Ext.panel.Panel', {
              id: 'accordion-panel',
              layout: 'accordion',
              tabBar: {
                  plain: true
              },
              border: false,
              items: [
                  {
                      id: 'accordion-1',
                      title: '1'
                  },
                  {
                      title: '2'
                  }
              ]
          });
  
          var tabPanel = Ext.createWidget('tabpanel', {
              activeTab: 0,
              defaults: {
                  autoScroll: true,
                  border: false
              },
              layout: 'fit',
              items: [
                  {
                      id: 'tab-1',
                      title: 'Tab 1',
                      layout: 'fit'
                  },
                  {
                      layout: 'fit',
                      title: 'Tab 2'
                  }
              ]
          });
  
          Ext.getCmp('tab-1').add(accordionPanel);
  
          var panel = Ext.getCmp('west-panel');
          panel.add(tabPanel);
          viewPort.add(mainLayout);
      }
  });
  </code></pre>