title: ExtJS border layout split resize doesn't work!
body: <p>I have a border layout with a grid and a panel, the grid is in 'center', the panel is in 'south'.</p>
  
  <p>The handle to resize the regions appears to work, but upon releasing the mouse, no change occurs, and the panels remain where they are.</p>
  
  <pre><code>var content = new Ext.grid.GridPanel({
                                    id: 'bug-grid',
                                    border: false,
                                    view: new Ext.grid.GroupingView(),
                                    region: 'center',
                                    plugins: [filters],
                                    store: bugStore,
                                    colModel: columnModel,
                                    trackMouseOver:false,
                                    loadMask: true,
                                    sm: new Ext.grid.RowSelectionModel({singleSelect:true}),
                                    listeners: {
                                        rowclick: {
                                            fn: function(grid, rowIndex, event) {
                                                var bug_id = grid.store.getAt(rowIndex).id;
                                                Ext.getCmp('activity-panel').load(activity_lines_path(bug_id));
                                            }
                                        }
                                    },
                                    bbar: new Ext.PagingToolbar({
                                                                    plugins: [filters],
                                                                    pageSize: pageSize,
                                                                    store: bugStore,
                                                                    displayInfo: true,
                                                                    displayMsg: 'Displaying bugs {0} - {1} of {2}',
                                                                    emptyMsg: "No bugs to display"
                                                                })
                                });
  var activity = new Ext.Panel({
                                   id: 'activity-wrapper-panel',
                                   region: 'south',
                                   items: getActivityPanel(),
                                   autoHeight: true,
                                   bodyBorder: false,
                                   border: false
                               });
  var page = new Ext.Panel({
                               id: 'page',
                               layout: 'border',
                               defaults: {
                                   split: true,
                                   frame: true
                               },
                               items: [content, activity],
                               renderTo: 'application',
                               height: 800
                           });
  </code></pre>