I suggest you have a look at how to build an app in MVC style because this is about connecting different views (=panel) together. http://docs.sencha.com/ext-js/4-1/#!/guide/mvc_pt1 is a good starting point (there are 3 parts). At the bottom of part 3 you will find the source code to download. I started learning Ext a few months ago by tweaking and modifying this Pandora project. It took me some time, but now this thing works amazingly fine and I'm wondering how one can do without MVC (of course you can, but...). Just my 2 cents...