Abstract: Tool bars are provided along lateral edges of a display of a handheld computing device. The tool bars include icons that represent application features. The user may interact with the application by touching the icons on the display. Since mobile computing devices are commonly held at the lateral sides of the device, navigation and activation buttons are in close proximity to a natural location of a user's thumbs. The proximity of the tool bars to the thumbs increases efficiency and accuracy when interacting with the application. The tool bars may be displayed in an expanded state such that a text label may be displayed to identify the application feature that each icon represents. The tool bars may also include functionality that displays additional information for any of the application features represented by the icons without navigating the application away from the current screen.