I tried that. I have no assembly appearances. When in the Hierarchy sort order, all of the faces that I have and want colored are accounted for. It's a model of an industrial air compressor in which the doors and some upper panels of the unit are yellow and the lower panels and roof are grey. While I'm in editing the part, all is well, but when I switch to the assembly, the lower panels are now yellow. They were never selected in the first place. When I right-click and try to remove the appearance from the now-yellow part, it won't go away. Could this be a glitch?