Scroll events really should be mouse events (*). This hasn't been too much of a problem in Morphic where we have a focus-follows-mouse policy. But in Tweak, for example, the keyboard scroll events go to the focused pane even when I point the mouse somewhere else.
AFAIK no host platform originally delivers scroll events as keyboard events, so it appears as the Right Thing to do, rather then hacking around it on the image side. However, I'm not sure about the best way to actually hand this to the image ... Any opinions?
As a further data point, there are mice having both vertical and horizontal scroll capabilities, something that users may want to put to use. Not sure if we should support the additional buttons, too, but why not? My mouse has 8 of them in total, all of which do something reasonable - yes I'm on a Mac ;-)
[OT] Rumor has it that Apple is going to introduce a new mouse soon, which may have two buttons or an iPod-like wheel or both ...
- Bert -
(*) Yes, I'm guilty for coming up with the arrow-key hack in the first place, but it was TSTTCPW