Ok want to make sure I understand sencha 2.x, specifically PR3. So this is valid (tried to copy/paste reduced example so sorry if there is a small syntax issue):

Code:
var lookupForm = {
  title: 'Lookup',
  autoRender   : true,
                modal        : true,
                hideOnMaskTap: false,
                height       : 505,
                width        : 480,
                centered     : true,
                fullscreen   : true,
  items: [
    {
      xtype: 'checkboxfield',
      label: 'My Reviews and Cellar'
    }, {
      xtype: 'checkboxfield',
      name: 'search_type',
      label: 'Friends'
    }, {
      xtype: 'checkboxfield',
      label: 'Internet'
    }]
  };


Ext.setup({
  onReady: function(){

    var bottomTabs = Ext.create('Ext.tab.Panel', {
      fullscreen: true,
      tabBar: {
        docked: 'bottom',
        ui: 'light',
        layout: {
          pack: 'center'
        }
      },
      items: [searchCard = Ext.create('Ext.tab.Panel', {
              title: 'Search',
              iconCls: 'search',
                items: [Ext.create('Ext.form.Panel', lookupForm)]
                })]

  })}
});
since it creates the form after the tabpanel after the outer panel, but this is invalid:

Code:
var lookupForm = Ext.create('Ext.form.Panel', {
  title: 'Lookup',
  autoRender   : true,
                modal        : true,
                hideOnMaskTap: false,
                height       : 505,
                width        : 480,
                centered     : true,
                fullscreen   : true,
  items: [
    {
      xtype: 'checkboxfield',
      label: 'My Reviews and Cellar'
    }, {
      xtype: 'checkboxfield',
      name: 'search_type',
      label: 'Friends'
    }, {
      xtype: 'checkboxfield',
      label: 'Internet'
    }]
});

var searchCard = Ext.create('Ext.tab.Panel', {
  title: 'Search',
  iconCls: 'search',
  items: [lookupForm]
});

Ext.setup({
  onReady: function(){

    var bottomTabs = Ext.create('Ext.tab.Panel', {
      fullscreen: true,
      items: [searchCard]
    });

  }
});
because the form was created before the tabpanel, etc? It appears to have rendering issues since the checkboxes are not checkable (although no errors in console)...or maybe this is a bug?