With AC11 we get Trace Reference - a very useful feature i wouldn't want to live without.
Trace reference allows you to screen either the active or underlying drawing. Often I'll screen the underlying drawing and make it a single color, gray for example.
Also often, I create composites of several drawings overlaying each other on a layout, similar to the manner in which I overlay drawings using trace reference.
Now I move to my layouts and I can't screen the underlying drawing - Sure, I could create a bunch of pensets and reduce the level of black for each individual pen for each level of screening I'd like, but before I ever get around to it, something a little less tedious comes up.
I wish for a screening slider in the Drawing setting dialog box.