Why do my parts get renamed when I change appearance or material?

 I like to keep my parts named, and try different colors, transparencies and/materials.
1.  ●Why do my parts get renamed every time I change any of those properties? The only time the parts keep their names is when I leave their original names, i.e. Part 3, but that is meaningless unless I have a project with about 5 parts.
2. ●How can I change appearance/materials of multiple parts in one shot? I can tag multiple parts, but it only changes properties of the last one I select the little triple dots on. BTW, I'm using Android app on Samsung Note 12.2 Pro
Thanks much,
R.L. Hamm