Strangely enough, Sencha Designer looked like it was giving me an error -- something like "Please associate a model .... inline data ... " on the TreeStore.
My question is if I fill out the root property why should I have to setup the data property (as the example does not bother to set the data property)? They both kind of seem to be doing the same thing exception the data property seems to work on an array of objects and root expects a dictionary object. I got my example to work by setting the data property to the empty list and setting the root property to what is in the sample code on the url.
Is there a good reason to have a data property for the TreeStore?
Here is the sample file. I tried to upload as an xda file, but it didn't like it. So I zipped it and it worked: Test2.zip. Note that I changed the data back to null so if you loaded it in the new sencha designer you can see the warning bubble. If you set the data property to , it goes away.