[RM2K] SKILLS THAT DON'T WORK - GREYED OUT IN BATTLE

I'm trying to make some new skills, but every time I go to try them in a test battle they're greyed out in the menu and all I get is the buzzer. It's not a matter of MP, this happens even when the skills cost 0.
I had this trouble once before recently, but then I resolved it by fidgeting around with the effect range until it eventually worked. Now it's just stuck no matter what I do. What is the cause of this and how can I stop it?

EDIT: Never mind, turns out I'm super dumb and picked a weapon attribute for the skill when only magic attributes work. Mystery solved.
EDIT2: Or not. Some skills work with some weapon attributes, but changing this one to a magic attribute made it work. I don't even know.