I ran into some hangups with this early on, too. You can add a listener to the list items to trigger the new panel:
Code:
var YourPanel = new Ext.Panel({
items: [{
xtype: 'list',
listeners: {
itemtap: function(list, index) {
DetailsPanel.dockedItems.items[0].setTitle('Selected Name'); // update toolbar title
DetailsPanel.setActiveItem('items_details', {type:'slide', direction:'left'}); // load new panel
}
}
}]
});
I commented the two events in there. One loads the new panel, which is what you were asking about. But I thought it would be helpful to know how to also update a toolbar to show a contextually-relevant title.
That should push you in the right direction.
Good luck.