If the right side box is very short, this algorithm gets a bit fussy. Not a problem for Amazon since their right side box is fixed height, but often a problem for menus where there is only one item in the sub-menu (usually because the sub-menu is programatically filled in.) You have to thread the needle moving your pointer to the right, because if you leave the line, it collapses the selection and selects the next item.
Even OS X has this issue, so if someone gets a good solution, they can beat Apple at their own game.