Mucking about with the Mighty Mouse and the latest release of iTunes while
listening to “A Northern Chorus” – cool Canadian artist if you’re into a
bit more of an ambient rock idea. In doing so, I noticed what I can only
describe as “enhanced for Mighty Mouse” behaviour. If iTunes 5 is the
active application, the scroll bars in the music/track display area
function just fine in 2d with the scroll ball. What I didn’t expect
exactly was the volume slider also acts like a scroll bar, and the active
region is location dependent.

Thus, if the pointer is over the table region, those scroll bars are
active and controlled via the the scroll bar, but moving the pointer
over the volume slider area, and the tracking region is slightly larger
than the volume slider graphic, enables the horizontal direction of the
scroll ball to control the volume slider. It’s actually quite intuitive,
but pleasantly so, and honestly given the bulk of apps out ther,
somewhat unexpected.

I would venture it’s exactly what should happen, but it does
represent a bit more coding and behaviour in the controls, changing
active regions properly. Although I haven’t delved deep enough into
Cocoa to know if that’s an almost-freebie. It could be via attaching
events in the nib, but I haven’t dabbled with components that much.

A good example of doing the right thing™.