A rendering engine that supports directional focus navigation, in response
to a directional input, shifts the focus to an appropriate focusable
element. The rendering engine determines one or more focusable elements
that are candidates to receive the focus based on the received
directional input and based on the relative display locations of the
focusable elements. The rendering engine selects the most appropriate
candidate focusable element based on each candidate element's display
location in relation to the display location of the element that
currently has focus.