Question: The default action to expand a node on ExtJS tree is double-click.

Before version 4, there is `singleClickExpand` property in TreeNode configuration.

How to apply `singleClickExpand` behavior on ExtJS version 4 tree ??

Is there a configuration property for this behavior without setting event listener??

Thank you.

Answer: 
I've spent some time looking for the same thing. I feel I can definitively answer your question with... 
No there isn't a config option for it. 
I had to set a click handler. I needed one anyway though to implement functionality for leaf clicks:

```
var tree = Ext.create('Ext.tree.Panel', {
    store: store,
    rootVisible: false,
    lines: false,
    useArrows: true,
    listeners: {
        itemclick: function(view, node) {
            if(node.isLeaf()) {
                // some functionality to open the leaf(document) in a tabpanel
            } else if(node.isExpanded()) {
                node.collapse();
            } else {
                node.expand();
            }
        }
    }
});

```
In fact you use the expand function of the treeview.

Just implement the itemclick function on you treepanel: 

```
listeners: {
    itemclick: function (treeview, record, item, index, e, eOpts) {
        treeview.expand(record);
    }
}

```