draw things using stuff like [self bounds] without being explicit

There are always judgement calls. I don't think I've ever published a tutorial that didn't result in somebody saying I left something out.

The tutorial would need to be twice as long to properly explain NSView, so I just decided to focus on the basic data structures, and cover more stuff in the next tutorial.

If something's too long, few people will get through it. Better to release something a bit shorter, even if there are gaps. The whole point is to reach people that were previously unreachable.

Also, keep in mind there's downloadable example at the end, which is at least a starting point for NSView. People can go in there and mess around if they want.

In addition, just calling -set on a colour probably wants you to be in some similar situation.

Not sure I follow. The -set method is explained in the tutorial.

The Drawing Groups sample code can probably be simplified even more by just using a single NSColor object

True but that would miss the point of the example, I think.

Thanks for the feedback.