A screen's button bar (SELECT and BACK under a list) steps sideways, so
once the wheel scrolled past a list's last row onto the bar it went back
and forth between the two buttons until a row was chosen again with the
mouse. A touch drag already left the bar with up and down, as the d-pad
does; the wheel now does the same.
(cherry picked from commit 2ddad079fa5435a70a383d757de16b960c421505)