More noob questions! Why can't I change my keys?

So I'm new on here and it seems like the first thing I ought to do is change from using my master key to log in to using a new posting key. However, I don't have the pencil button I'm supposed to have:

Is this a temporary change due to The Hack? Or is my browser broken and not displaying the little pencil?

Is it a real problem that I can't change keys?

And once I put the secret key into the web UI, isn't it sort of compromised? Can I keep my master key on my machine and only give steemit.com the posting key?