Group Color Assignment Bars Gone Missing?

[right beside]

I posted about this in the PT 10 forum, but had no luck there.

Out of nowhere, some of the little color bars that appear to the left of group names in the group menu section have disappeared, and in the edit window, those groups no longer have a color assignment at all.

I've never seen this and can't figure out how to bring them back.

Is there even an option to turn the color for different groups completely on
or off, while leaving others alone?

Or is this a bug?

Look at the group menu in the picture below. Do you see how some of the groups are missing a color bar to the left of their name? Where did they go? The groups are still enabled, they just have no color in the edit window, which confuses things if there are multiple colorless groups next to each other in the edit window.

I've searched for the answer and watched a few tutorials, but haven't found anyone or anything mention enabling/disabling just a groups color.

Thanks.