Basic Question

[Piestar]

My question is so basic, I feel a bit silly, but I looked about a bit and couldn't find the answer....

I downloaded forge, and a few MODS. When I start up Minecraft I get two options, regular and forge, I use Forge when I want to try out a mod. When I look at the mods, some have a disable button, some are blocked out, some are clickable and black, some are clickable and purple. When I click on those, the button reacts as if clicked, but nothing changes? Very odd. How do I know which MODS are active, and which aren't? Does the pink imply a conflict? Why can I not tell the difference between disabled and not? 

Sorry if I missed something obvious, but it's a bit frustrating.

[Piestar]

Addendum:When i start the game, the version (1.12.2) is highlighted in red, is that a problem?

[Piestar]

Ahhh, thanks. Is there any difference between the black lettered ones and the red or purple lettered ones?

[Piestar]

Thanks... good to know.