The source code

    /**
     * @class Ext.Element
     */
    Ext.Element.addMethods({
        /**
         * Initializes a {@link Ext.dd.DD} drag drop object for this element.
         * @param {String} group The group the DD object is member of
         * @param {Object} config The DD config object
         * @param {Object} overrides An object containing methods to override/implement on the DD object
         * @return {Ext.dd.DD} The DD object
         */
        initDD : function(group, config, overrides){
            var dd = new Ext.dd.DD(Ext.id(this.dom), group, config);
            return Ext.apply(dd, overrides);
        },

        /**
         * Initializes a {@link Ext.dd.DDProxy} object for this element.
         * @param {String} group The group the DDProxy object is member of
         * @param {Object} config The DDProxy config object
         * @param {Object} overrides An object containing methods to override/implement on the DDProxy object
         * @return {Ext.dd.DDProxy} The DDProxy object
         */
        initDDProxy : function(group, config, overrides){
            var dd = new Ext.dd.DDProxy(Ext.id(this.dom), group, config);
            return Ext.apply(dd, overrides);
        },

        /**
         * Initializes a {@link Ext.dd.DDTarget} object for this element.
         * @param {String} group The group the DDTarget object is member of
         * @param {Object} config The DDTarget config object
         * @param {Object} overrides An object containing methods to override/implement on the DDTarget object
         * @return {Ext.dd.DDTarget} The DDTarget object
         */
        initDDTarget : function(group, config, overrides){
            var dd = new Ext.dd.DDTarget(Ext.id(this.dom), group, config);
            return Ext.apply(dd, overrides);
        }
    });