Focus issue with firefox and tinyMCE

Focus issue with firefox and tinyMCE

I have a js fiddle to show this -  here . First, click the button to launch a jQuery Dialog. Then once the tinyMCE editor loads, click in a text field and then into the tinyMCE editor. Now click in a different text field. Notice that the text field that was previously focused gets focus back and not the field that is clicked. This does not happen in Safari but does happen in Firefox. This only happens if the dialog is a modal dialog. This is using tinyMCE 4, jQuery 1.9, and jQuery UI 1.11.  Any help in getting around this issue would be great.