Hearthpwn

Weird. I just went to Chrome (where I was not logged in) to post a screenshot of what I saw; meanwhile, I had briefly gone into my settings on this browser where I am logged in, and fiddled with something under My Account, "Manage Twitch Account." I didn't do anything but click on it; it redirected me to Twitch, as I was already logged in on Twitch.

I then went back to Chrome, clicked on the "Log in with your Twitch account" and even though I entered no password, username or login information, it magically logged me in.

Is it necessary to be logged in to one's Twitch account before logging on to Hearthpwn? 

Here is the screenshot of what I saw:

I am using a web browser where I am still logged in to Hearthpwn to post this. 

I merged my Hearthpwn and Twitch accounts a couple of months ago.

Today, I am trying to log in from another browser (no trouble in the past).  The Hearthpwn log-in page presents the two options, log in with Hearthpwn or log in with Twitch.  I want to use my Hearthpwn username, so I choose log in with Hearthpwn. 

I tried entering my Hearthpwn forum name, then I tried entering my Twitch name, which is different.  I did all of this under the "log in via Hearthpwn" portion. I *think* I tried once to log in via the Twitch one, but am not certain.  I don't want to get locked out of my account. 

How do I log in using my Hearthpwn credentials? Which box do I use, the Hearthpwn box or the Twitch box? Thanks.