Hello all,

I have nested models like here:

Code:
// define the User model
Ext.define('User', {
    extend: 'Ext.data.Model',
    fields: ['id', 'name', 'age', 'gender'],
    validations: [
        {type: 'presence', name: 'name'},
        {type: 'length',   name: 'name', min: 5},
        {type: 'format',   name: 'age', matcher: /\d+/},
        {type: 'inclusion', name: 'gender', list: ['male', 'female']},
        {type: 'exclusion', name: 'name', list: ['admin']}
    ],


    proxy: {
        type: 'rest',
        url : 'data/users',
        reader: {
            type: 'json',
            root: 'users'
        }
    },


    hasMany: 'Post' // shorthand for {model: 'Post', name: 'posts'}
});


//define the Post model
Ext.define('Post', {
    extend: 'Ext.data.Model',
    fields: ['id', 'user_id', 'title', 'body'],


    proxy: {
        type: 'rest',
        url : 'data/posts',
        reader: {
            type: 'json',
            root: 'posts'
        }
    },
    belongsTo: 'User',
    hasMany: {model: 'Comment', name: 'comments'}
});


//define the Comment model
Ext.define('Comment', {
    extend: 'Ext.data.Model',
    fields: ['id', 'post_id', 'name', 'message'],


    belongsTo: 'Post'
});
I need to display three combo-boxes: User, Post, Comment. The combo-boxes should be in the master-detail relationship (cascading). I haven't found any information on how to do it. Any ideas?