res:launcher:: fix selected item problem.

unselect item when the selected item is not in viewport.

tower: https://tower.im/projects/8f19f0bf0e754f0b82ef2c24bc230973/todos/afc47bf8abf644c292fbaf095469474d/

Change-Id: I847d9542103ead2027ef23c197f6464e60490c56