Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for adapting user interfaces for devices that include widescreen displays. In one aspect, a method includes determining a size characteristic of a display of a mobile device, determining a size characteristic of content that is to be displayed on the display, and comparing the size characteristic of the content to the size characteristic of the display. The method also includes selecting one or more controls to display in a portion of the display that is not to be used to display the content based on comparing the size characteristic of the content to the size characteristic of the display, displaying the content, and displaying the selected controls in a portion of the display that is not used to display the content.