I guess I'm in the minority, but not only does this behavior not bother me, for me it's a feature. Most of the time, if I'm trying to draw outside the boundary

I guess I'm in the minority, but not only does this behavior not bother me, for me it's a feature. Most of the time, if I'm trying to draw outside the boundary, then it's because I've got the wrong layer selected. So it saves me from drawing on the wrong layer and then having to deal with trying to get the changes moved to the correct layer. In cases where the above doesn't hold (i.e., I actually want to draw inside the smaller layer), then it's easy enough to expand the layer's size. Different strokes for different folks, I guess.