I am trying to drag an item from a tree to the tab panel but it is not working.

this is what i've done so far:

        var compositeItem = new Ext.tree.TreeNode({
            text: 'Item',
            id: 'comp',
            enableDD: true,
            dropConfig: {
                ddGroup: 'TreeDD',
                dragData: {
                    name: "Start"

        //add drop target for group
        var droptarget = new Ext.dd.DropTarget("center1", {
            ddGroup: 'TreeDD'

        droptarget.notifyDrop = function(dd, e, data){
            if (data.name) {
                //add flow here
                return true;
When I drag and drop, the notify event is not triggered. What am I doing wrong? Thanks in advance for any help.