layout+attachAccordion cannot show the default skin

Dear Sir,

I used the dhtmlxSuite_v502_pro, when I set layout(2U) + attachAccordion in cell(“a”). It can not set the accordion Skin.
But I saw the doc[url]http://docs.dhtmlx.com/accordion__skins.html[/url]. the “material” is default. I just need the material skin.
please help.
But when I change anouther Skin ,It is also not possible to display the skin.

Many Thanks.

[code]

<?php session_start(); ?> Main html, body { width: 100%; height: 100%; margin: 0px; padding: 0px; background-color: #ebebeb; overflow: hidden; }
<script>
	
    var myLayout,myAcc,myTree1,myTree2,myTree3,myTree4,myTree5;
    function doOnLoad() {

        myLayout = new dhtmlXLayoutObject({
            parent: document.body,
			pattern: "2U",
			skin: "material",
            cells: [
                { id: "a", text: "A", header: "false" },
                { id: "b", text: "B", header: "false" }
            ]
        });
	 
        myLayout.cells("a").setWidth(300);
	 		
        myAcc = myLayout.cells("a").attachAccordion({
			icons_path: "../dht/skins/accordionIcon/",
			skin: "material",
            items: [
            	{ id: "a1", text: "Favorites", icon: "flag_red.png" },
				{ id: "a2", text: "Company Profile", icon: "flag_green.png" },
				{ id: "a3", text: "Add Product", icon: "flag_blue.png" },
				{ id: "a4", text: "Account View", icon: "flag_magenta.png" }
			]
        });
		//myAcc.setSkin("dhx_web");
		
    }

</script>
[/code]


Be sure that you have included the css file of the skin

For web skin it will be

snippet.dhtmlx.com/dd8e81f6e