Table class in table layout

[mykola]

Hi! I'm new to ext-js, and i don't understand how to apply a style class to a table that is formed by table layout. I tried to write it into extraCls property of layoutConfig, but it didn't work. Is there any 'tableCls' property (like 'cellCls')?
There's a sample code:

    northPanel = new Ext.Panel({
        region: 'north',
        layout:'table',
        split:true,

        layoutConfig: {
            extraCls: 'gl_tab',
            columns: 3
        },
        items: [{
            html: 'Back',
            cellCls: 'back'
        },{
            html: 'Title',
            cellCls: 'zag'
        },{
            html: 'Search',
            cellCls: 'search_bl'
        }]
    });