dialog.open() does not return reference to self when dialog is already opened

dialog.open() does not return reference to self when dialog is already opened.

Example:

$element.dialog().dialog('open')

Problem:

there is a check inside the open() method (see jquery.ui.dialog.js line 307):

if (this._isOpen) { return; }

Expected:

if (this._isOpen) { return this; }