TLDR I want my treepanel from EXTJS to remember its previous settings. ExtJS-3.2.1

I have seen this done before for ExtJS-2.x.x :See here on the extjs forums.
But as seen as they are pretty much lifeless, with threads on there asking this question or similar with no reply for up to 6months. I thought I would bring it here.

I need to be able to get my treePanel to remember previous opened folders and which boxes are checked. It is async treePanel.

Panel is as follows:

 var layerTree = new Ext.tree.TreePanel({
                    border: true,
                    region: "east",
                    title: 'LayersTree',
                    width: 250,
                    split: true,
                    collapsible: true,
                    collapsed: true,
                    iconCls: 'treePanelIcon',
                    enableDD: true,
                    autoScroll: true,
                    //pulls in layers and their attributes//
                    root: new Ext.tree.AsyncTreeNode({ leaf: false,
                        loaded: false,
                        expanded: true,
                        text: 'Tree Root',
                        children: treeLayers
                    })

Am using ExtJS-3.2.1, GeoExt, OpenLayers.

Anyone done this before or know how to do it? (Preferably with a plugin but any answer is appreciated)