I noticed this when my tree panel view was not updating when passed a model which had not fully loaded. In the fiddle below you'll see a root node appear empty which is because at the time of setting the root node all attributes besides id had not been loaded in yet.

I narrowed this down to TreeStore.applyRootNode which only sets the store and treeStore properties on the node if it was not a model first. My override for this is included in the fiddle but I'll also include it here.



Code:



Ext.define('Test.override.data.TreeStore',{
    override : 'Ext.data.TreeStore',
    applyRoot : function(newRoot){
        newRoot = this.callOverridden(arguments);
        if(newRoot){
              newRoot.store = newRoot.treeStore = this;  
        }
        return newRoot;
    }
});

Offending code from Ext.data.TreeStore



Code:



applyRoot: function(newRoot) {
        var me = this,
            Model = me.getModel(),
            idProperty = Model.prototype.idProperty;


        // Convert to a node. Even if they are passing a normal Model, the Model will not yet
        // have been decorated with the constructor which initializes properties, so we always
        // have to construct a new node if the passed root is not a Node.
        if (newRoot && !newRoot.isNode) {
            // create a default rootNode and create internal data struct.
            newRoot = Ext.apply({
                text: me.defaultRootText,
                root: true,
                isFirst: true,
                isLast: true,
                depth: 0,
                index: 0,
                parentId: null,
                allowDrag: false
            }, newRoot);
            if (me.defaultRootId && newRoot[idProperty] === undefined) {
                newRoot[idProperty] = me.defaultRootId;
            }


            // Specify that the data object is raw, and converters will need to be caled
            newRoot = new Model(newRoot);
            
            // The root node is the only node bound to the TreeStore by a reference.
            // All descendant nodes acquire a reference to their TreeStore by interrogating the patrentNode axis.
            // The rootNode never joins this Store. It is bound and unbound in applyRoot and updateRoot
            newRoot.store = newRoot.treeStore = me;
        }
        return newRoot;
    },