JQM 1.4 selectmenu widget overlay not set by data-overlay-theme option... always theme "a"

JQM 1.4 selectmenu widget overlay not set by data-overlay-theme option... always theme "a"

I created an example at http://jsbin.com/IFolanOW/90/edit using the recommended github template. I'm using the new selectmenu widget in jqm 1.4. The issue appears in firefox, chrome As you can see there are several selectmenu widgets on the page. Two (Instruments and Genres) are long enough that they trigger the behavior where the select menu opens as a dialog. They are styled: data-theme='b' data-overlay-theme='b'.... It appears when I inspect that dialog that the body of the dialog page has a class that causes the style of the overlay to always be "a". Setting the data-theme-overlay option on the selectmenu widget per the docs has no effect. What did I do wrong? How can I style the overlay?