This is an idea which is currently experimental but is a very good visual cue for helping with color choices. There's a line in the color selector to help people figure out what is a good contrast for color choices. You can see it at the 10 min mark. https://www.youtube.com/watch?v=dJR-n8szgBc&index=13&list=PLNYkxOF6rcICcHeQY02XLvoGL34rZFWZn
Triaging (filter on CLIMBING SHOES).
Inspector bug triage (filter on CLIMBING SHOES).
See also bug 1332090 for a similar feature request (which has been worked on and, although still behind a pref, might come soon).