How to disable multiple selection of nodes in dijit.Tree?

http://stackoverflow.com/questions/12261723/how-to-disable-multiple-selection-of-nodes-in-dijit-tree

by phusick

HTML

<link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/dojo/1.8/dijit/themes/claro/claro.css">
<script src="http://amd.egoworx.com/jsfiddle-dojo-require.js"></script>
<script type="data/json" id="earth">
[
    { id: "earth", name:"The earth", type:"planet", population: "6 billion"},
    { id: "AF", name:"Africa", type:"continent", population:"900 million", area: "30,221,532 sq km",
            timezone: "-1 UTC to +4 UTC", parent: "earth"},
        { id: "EG", name:"Egypt", type:"country", parent: "AF" },
        { id: "KE", name:"Kenya", type:"country", parent: "AF" },
            { id: "Nairobi", name:"Nairobi", type:"city", parent: "KE" },
            { id: "Mombasa", name:"Mombasa", type:"city", parent: "KE" },
        { id: "SD", name:"Sudan", type:"country", parent: "AF" },
            { id: "Khartoum", name:"Khartoum", type:"city", parent: "SD" },
    { id: "AS", name:"Asia", type:"continent", parent: "earth" },
        { id: "CN", name:"China", type:"country", parent: "AS" },
        { id: "IN", name:"India", type:"country", parent: "AS" },
        { id: "RU", name:"Russia", type:"country", parent: "AS" },
        { id: "MN", name:"Mongolia", type:"country", parent: "AS" },
    { id: "OC", name:"Oceania", type:"continent", population:"21 million", parent: "earth"},
        { id: "AU", name:"Australia", type:"country", population:"21 million", parent: "OC"},
    { id: "EU", name:"Europe", type:"continent", parent: "earth" },
        { id: "DE", name:"Germany", type:"country", parent: "EU" },
        { id: "FR", name:"France", type:"country", parent: "EU" },
        { id: "ES", name:"Spain", type:"country", parent: "EU" },
        { id: "IT", name:"Italy", type:"country", parent: "EU" },
    { id: "NA", name:"North America", type:"continent", parent: "earth" },
        { id: "MX", name:"Mexico", type:"country",  population:"108 million", area:"1,972,550 sq km",
                parent: "NA" },
            { id: "Mexico City", name:"Mexico City",...

CSS

html, body {
    width: 100%;
    height: 100%;
}

JavaScript

require([
    "dojo/_base/window",
    "dojo/dom",
    "dojo/store/Memory",
    "dojo/store/Observable",
    "dijit/tree/ObjectStoreModel",
    "dijit/Tree",
    "dojo/domReady!"
], function(
    win,
    dom,
    Memory,
    Observable,
    ObjectStoreModel,
    Tree,
    _dndSelector,
    dndSource        
) {
   
    var store = new Memory({
        data: eval(dom.byId("earth").textContent)
    });
    
    store.getChildren = function(object){
        return this.query({parent: this.getIdentity(object)});
    };
    
    store = new Observable(store);
    
    var model = new ObjectStoreModel({
        store: store,
        query: {id: "earth"}
    });
    
    var tree = new dijit.Tree({
        id: "tree1",
        model: model,
        persist: false
    }).placeAt(win.body());
    
    tree.dndController.singular = true;
    
});