I have been using SolidWorks for about a year for relatively simple stuff: making parts, creating assemblies, and making construction drawings. I recently downloaded 2010 and really like that they fixed the mirror function in Assemblies. It was just about un-usable in 2009. One source of frustration for me is the way bringing a new part into an assembly and mating it to other parts causes problems with half the names of components in the list turning that yellowish-brown color. I am always careful to have fully defined sketches and parts, and all parts in an assembly fully definedby mating before I bring in a new one, so that's not it. Part of the time I can fix it by hitting the rebuild button at the top of the screen, and most of the rest of the time I can fix it by opening a linear component (usually the first one in the assembly) to edit, and clicking the green check mark without making any changes. So, I know how to fix it but would like to know how to make it stop.