extjs shadow bug when dragging panels

Question

I have three panels in my Ext JS project; That is one panel as a parent panel and two others are child panels. I've set the child panels to be draggable.
As you can see in the code below:

extend: 'Ext.tree.Panel',
requires: ['Ext.data.TreeStore'],
collapsible: true,
border: false,
draggable: true,
resizable: true,
floating: true,
constrain: true,
renderTo: Ext.getBody(),
store: new Ext.data.TreeStore({
//data.jason
}),
listeners: {
    move: 'onDrag'
}

//onDrag function is:

onDrag: function(stick)
{
   stick.dd = new Ext.dd.DDProxy(stick.el.dom.id,'group');
   drag = stick;
   drag.anchorTo(Ext.getBody(),"tl-bl?");
   drag.setHeight(490);
   drag.setMinHeight(200);
}

My problem is that when I drag the child panels they leave some shadow on the former place:

How can i solve this?

Answer 1

Extjs has a habit of not updating its shadows.

Try drag.syncShadow();