Hello everybody!

I've a problem with the method add(). My FormPanel doesn't render. I'm using RowExpanderPlugin with Grids. When I expand some row, a FormPanel should be rendered with use of LayoutManager.
so here's my Code:
Code:
function expandGrid(record,index) {
  var formPanel1 = new Ext.FormPanel({
      id: 'id', 
      items: [ {title: "title1"} ]
 });
var panel = new Ext.Panel({
                id:'main-panel'+index,
                baseCls:'x-plain',
                renderTo: Ext.getBody(),
                layout:'table',
                layoutConfig: {columns:2},
                // applied to child components
                defaults: {frame:true },
                renderTo: 'remData'+index,
}
now when I use panel.add() it doesn't work:
Code:
panel.add(formPanel1);
panel.doLayout();
but when I define this static:
Code:
    var panel = new Ext.Panel({
                id:'main-panel'+index,
                baseCls:'x-plain',
                renderTo: Ext.getBody(),
                layout:'table',
                layoutConfig: {columns:2},
                // applied to child components
                defaults: {frame:true },
                renderTo: 'remData'+index,
                items:[
                    personPanel  
]
});
then it works, but I don't want to use this solution but the first one with .add()
could anyone help me and say how should it be solved ?

thank you for all your answers