ExtJS 6 store.remove(records) -> store.sync() don't trigger the server
<p>I use ExtJS 6.0.0, REST proxy with TreeStore. So when i remove some records from the store <em>store.remove(records)</em>, then try to sync changes with server and call <em>store.sync()</em> and nothing happend! A callback function of sync not called.</p>

<p>url: '/admin/pages', return simple nested data in proper format.
View and update operations work well.</p>

<p>I made a simple code fragment just to illustrate the issue:</p>

<pre><code>    Ext.define('Pages', {
        extend: 'Ext.data.TreeModel',
        fields: [
            {name: 'id',     type: 'int'},
            {name: 'parent_id', type: 'int'},
            {name: 'title', type: 'string'}
        ]
    });

    Ext.onReady(function() {

        var store = Ext.create('Ext.data.TreeStore', {
            model: 'Pages',
            proxy: {
                type: 'rest',
                url: '/admin/pages',
            }
        });

        var tree = Ext.create('Ext.tree.Panel', {
            width: 500,
            height: 300,
            renderTo: Ext.getBody(),
            rootVisible: false,
            store: store,
            multiSelect: true,
            columns: [{
                xtype: 'treecolumn',
                text: 'title',
                sortable: true,
                dataIndex: 'title'
            }],
            tbar: [
                {
                    text: 'Delete',
                    handler: function () {

                        var records = tree.getSelection();
                        store.remove(records); // remove nodes from tree
                        store.sync(); // do nothing!! WHY?

                    },
                }
            ]
        });
</code></pre>