Activating an email tempalte!?!

Hello SI team

I know this should be a no brainer.
In ES>E-Mails>Template Editor
I have a list of emails for different actions.

In my case I am interested in activating an email for a discussion.

So I go to this item here: "discussion.reply.php" and in the far right column I click on the red X where “modified” is.

I would have thought that this publishes this item and that I would get a green tick!

But instead what happens is that I am:

a) brought here ES>E-Mails>Activities.
b) When i navigate back here: ES>E-Mails>Template Editor the red X is still there!?!

What am I missing

thanks

Paul