Tweet button loads but is not visible IE9


I’m using the standard JS to load the Tweet button. IE9 runs the script, and the elements for the button are generated, but they are not visible. Other buttons drawn in a similar way on the page (FB share, for instance) display correctly. The button lives inside of a flyout that is only visible during a hover state. The flyout is the right size/position (it gets its h/w from the contained iframe instantiated by the js), but all I see is white background. Getting no JS errors and I’ve tried playing with positioning/z-indices.