* Link to the upstream bug report.
* No need to specify the default value for an option.
* Use the new _super() UI method to open the dialog, avoiding a direct reference to the parent.
* Fix typo in comment.
* Use public isOpen() method rather than a private property.
props scott.gonzalez.
fixes#22399.
git-svn-id: https://develop.svn.wordpress.org/trunk@22514 602fd350-edb4-49c9-b593-d223f7449a82