Working on a popup menu displayed when an app bar icon button is clicked (similar to the Respond button submenu in the standard Email WP app). How can I position a control like StackPanel over the app bar when the app bar is visible?
In Windows Phone Application Bar is a system control, so it is created by system and appears "on" your application. You can try to use third-party control for Application Bar or try to calculate position for your StackPanel manually dependent on screen size and orientation.