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 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?