NOT a new file, it is one that has been in progress for some considerable time. These parts were fine before, no transparency issues whatsoever. Today, I open up several files, and there are parts showing through, even though the parts that are transparent are set to 100% opaque. This is now getting very old.... something is unstable, and while I am sure this will be blamed on me, or on the imported parts, I think it deserves a specific CAUSE being explained. Do I REALLY need to supply files yet again? The parts that show through are usually imported files, STEP files. I do not understand how an imported part gets to over-ride parameters on other parts and cause them to become become transparent. Bigseb has mentioned issues importing parts, and it appears that he is correct, something is not right with the part importing. That business of how one part gets to over-ride another's parameters seems to be the point here. If one part is set to be opaque, it seems as if that should be absolute. In this particular case, everything is generally to the same scale, so it is not, or should not be, a matter of the "zoom out problem" where the scale is such that the distance between parts passes the threshold at which Alibre recognizes one part as being "behind" another. Yes, of course I HAVE closed Alibre and re-opened. Nothing changed.