A couple of suggestions related to scrollwheels.

1) It would be good to clarify behavior for vertical vs horizontal scrollwheels where both exist.
2) KDE and MS use Alt/Meta scroll to flip directions (or at least they sort of do)

In Gnumeric I've adopted the following conventions

ctrl  + either wheel == zoom (up/left == zoom out)
shift + either wheel == show/hide detail (possibly gnumeric specific)

alt flips orientation of wheel
eg alt vert wheel == horiz and vice versa

KDE only flips vertical -> horizontal with alt, but apparently does not flip
horizontal to vertical.