Question

This code is working in Extjs 4.0.2a
but when converted to 4.1 it no longer works and gives an error

Uncaught TypeError: Cannot call method 'query' of undefined

Ext.onReady(function() {

    var panel = new Ext.Panel({
        renderTo: divtag,
        draggable: {
            insertProxy: false,
            onDrag: function(e) {
                var el = this.proxy.getEl();
                this.x = el.getLeft(true);
                this.y = el.getTop(true);
            },
            endDrag: function(e) {
                this.panel.setPosition(this.x, this.y);
            }
        },
        title: 'Panel',
        width: 200,
        height: 100,
        x: 20,
        y: 20
    });
});

Answer 1

Apparently there is a bug in this version of Ext. It wont work even if you try default D’n’D for panel like this:

Ext.onReady(function() {
    var panel = new Ext.Panel({
        renderTo: 'divtag',
        draggable: true,
        title: 'Panel',
        width: 200,
        height:100,
        x: 20,
        y: 20
    }); //panel.show(); });
});

I menage to patch the code to work the way you want it, this code should work:

Ext.onReady(function() {
    var panel = new Ext.Panel({
        renderTo: 'divtag',
        draggable: {
            insertProxy: false,
            onDrag: function(e) {
                var el = this.proxy.getEl();
                this.x = el.getX();
                this.y = el.getY();
            },
            endDrag: function(e) {
                panel.setPosition(this.x,this.y);
            },
            alignElWithMouse: function() {
                panel.dd.superclass.superclass.alignElWithMouse.apply(panel.dd, arguments);
                this.proxy.sync();
            }
        },
        title: 'Panel',
        width: 200,
        height:100,
        x: 20,
        y: 20
    }); //panel.show(); });
});

As a side note I should probably advice you not to do this anyway, because you can define your own DD for panel that you can use, and even better Ext already have one defined, so you can just override Ext panel to use default Ext.util.ComponentDragger, or in code, I advice you to do this:

Ext.override(Ext.panel.Panel, {
    initDraggable: function() {
        var me = this,
            ddConfig;

        if (!me.header) {
            me.updateHeader(true);
        }

        if (me.header) {
            ddConfig = Ext.applyIf({
                el: me.el,
                delegate: '#' + me.header.id
            }, me.draggable);

            // Add extra configs if Window is specified to be constrained
            if (me.constrain || me.constrainHeader) {
                ddConfig.constrain = me.constrain;
                ddConfig.constrainDelegate = me.constrainHeader;
                ddConfig.constrainTo = me.constrainTo || me.container;
            }

            me.dd = Ext.create('Ext.util.ComponentDragger', this, ddConfig);
            me.relayEvents(me.dd, ['dragstart', 'drag', 'dragend']);
        }
    }
});
var panel = Ext.create('Ext.panel.Panel', {
    id: 'test',
    renderTo: 'divtag',
    draggable: true,
    floating: true,
    title: 'Panel',
    width: 200,
    height:100,
    x: 20,
    y: 20
});

Code for a initDraggable function in panel override is taken from current stable version of Ext.window.Window.initDraggable method.