This relates to a 2011 Macbook Pro running El Capitan.
I'm set up as the admin and my child has a standard account with parental controls enabled. My child forgot their password and I'm trying to reset it in System Preferences. I unlock the padlock with the admin password, but my child's account is still grayed out and I can't select it to reset the password.
This also happened about a month ago but one day suddenly I could select their user account and I successfully reset the password. I don't know why I suddenly could select it, and I don't know why I now suddenly can't select it. I tried locking and unlocking the padlock but it doesn't make a difference.
I know how else I can reset the password, but what I'm asking here is:
What circumstances could explain why I can't select the user account after unlocking the padlock with my admin password?