Color picker wont allow pure black (RGB 0, 0, 0)

Is it just me or…is there a bug with the color picker?
Won’t let me create a pure black swatch (RGB 0, 0, 0) - always pushes me back to 28, 28, 28.
Anyone else experiencing this?

It’s not a bug, it’s set up with certain limits of this nature.

It would be great if such things were mentioned in the manual.
Thanks for the info.