You can remove the following lines from your code if you don't using dhtmlxWindows in your app

    <link rel="stylesheet" type="text/css" href="../../../dhtmlxWindows/codebase/dhtmlxwindows.css">
    <link rel="stylesheet" type="text/css" href="../../../dhtmlxWindows/codebase/skins/dhtmlxwindows_dhx_blue.css">
    <script src="../../../dhtmlxWindows/codebase/dhtmlxwindows.js"></script>

In other words you should remove all js/css includes of dhtmlxwindows.js, dhtmlxwindows.css and skins/dhtmlxwindows_[skin name].css

This is recommended way to getting more performance.

Container is a common module used in layout, windows, accordion.

Just add

    <link rel="stylesheet" type="text/css" href="codebase/dhtmlxcontainer.js">

dhtmlxLayout will no work without it.

By the default skin is dhx_skyblue (the new one in 2.5 version), but you also can use old dhx skin, dhx_blue and dhx_black.

Skin autodetection means detect and set corresponding skin by the layout itself depending on attached css skin file.

To set not default skin you shoyuld pass corresponding skin name as 3-rd argument into layout's constructor (also change skin on-the-fly feature appears in 2.5 version).

But now it no needed to set skin to layout. Skin will inherit to all attached components in the layout.

Just include needed skin css

    <link rel="stylesheet" type="text/css" href="codebase/skins/dhtmlxlayout_dhx_blue.css">

And init layout with 2 arguments

    var dhxLayout = new dhtmlXLayoutObject(document.body, "3L");

And layout will automatically set skin to “dhx_blue” to itself and all attached components.