How can references of Drawing Views be made to appear shaded/gray color in the Sheet Model.
In the Sheet Model, click "Settings > Adjust Colors" from the Reference dialog box.
Once in the "Adjust Reference Colors" box adjust the color in the "Saturation" bar.
There is also the option to set a single hue for all referenced colors.
Help topic: "Adjust Reference Colors Dialog"
Adjust Colors Setting from Nested Reference Attachments