Throughout Bluebeam Revu, color selections (dropdowns) allow for a color to be input using Hex code in addition to RBG. See the snip below.
However, when selecting the Change Colors… option in Properties | Appearance, the pop up dialog is completely different. As shown below, not only does this look like a different company worked up the routine, there IS NO ability to to enter a Hex value for a color. THIS IS VERY ANNOYING!
This is a clean up issue in the interface.