[4.1.2] Unable to sort tree node in an un-rendered tree

[lagnat]

"ext-all-debug.js:96394TypeError: 'undefined' is not an object (evaluating 'me.el.child')"

Ext.onReady(function() {

        var store = Ext.create('Ext.data.TreeStore', {
            root: {
                expanded: true,
                children: [
                    { text: "detention", leaf: true },
                    { text: "homework", expanded: true, children: [
                        { text: "book report", leaf: true },
                        { text: "alegrbra", leaf: true}
                    ] },
                    { text: "buy lottery tickets", leaf: true }
                ]
            }
        });

        var tree = Ext.create('Ext.tree.Panel', {
            title: 'Simple Tree',
            width: 200,
            height: 150,
            store: store,
            rootVisible: false,
            store: store
        });

        //tree.render(Ext.getBody());

        tree.getRootNode().sort(function(n1, n2) {
            var v1 = n1.data['text'].toUpperCase();
            var v2 = n2.data['text'].toUpperCase();

            if (v1 < v2)
                return -1;
            else if (v1 > v2)
                return 1;
            return 0;
        });     
});

[mitchellsimoens]

This has been fixed for 4.1.3