滚动时Jquery移动弹出窗口ui-popup-screen不跟随

I have a JQM 1.3 popup which I have set to data-dismissible="true" All is good until the screen is scrolled. The popup scrolls fine and I have a javascript event listener to center the popup when the scrolling stops. The problem is that the underlying -screen div (that jqm creates) does not follow the popup. So if I scroll to the bottom of the screen and then click anywhere outside of the popup it does not dismiss the popup. Using the dev tools I can see that the css for the -screen div never changes after the popup is displayed.I have a JQM 1.3 popup which I have set to data