Yeah, unfortunately that only applies for raster engraves. For vectors, color is the determining factor…black will go first, then blue, then green, red, orange, yellow - progressively getting lighter as you move down the thumbnail column. (hey, everyone likes a challenge, right?)
There is a set of Glowforge based colors that you can load into your software to make color selection a bit easier… @marmak3261 worked it out a while back:
