This is similar to the mouse button down handling. When the map mode is
disabled and the map mode is in twips, then in general it's possible to
send mouse coordinates in twips. The scrollbar is usually in pixels, so
add extra code to still make this possible.

Change-Id: I0c7e404ecd7ac839e000266e396683bb7d15c505
(cherry picked from commit d7acb44b)