non-artists. And it is quite useful to be able to know that you can lock a layer, do a rubberband across the canvas to select all objects of my unlocked layers and not have to worry about anything in my locked layer getting selected as well. In Illustrator & Freehand (as well as others) that is the behavior.
Sure. Selecting is now mostly prevented, as I wrote in the previous message (the Find dialog and the Tab key selection still need fixing). However if you do manage to select it, I don't think we should prevent changing it. We must have at least one way to select locked objects if the user so prefers (I think I'll add a "search locked" checkbox to the Find dialog for this).
Also, as I just tested in Illustrator, if you have an object selected and lock the layer it's on, it is automatically deselected (as you can't modify something that is locked). That makes sense to me as well.
I'm still undecided on this one. It makes sense to deselect, but it is useful to leave them selected for a while (e.g. to be able to unlock them at once, or evacuate to another unlocked layer).
If we separate unselectable and immutable into separate layer-level options it would make sense to all of us geeks. But most artists aren't really geeks and don't want separate functions, it just needs to do what they expect.
We don't need a separate immutability imho. Unselectability is enough. It's still possible to change an unselected object, e.g. by changing a gradient or pattern that it uses, but this is becoming less of a problem now that we don't share gradients across objects by default.