Remove red box on raid frames?

Gameplay Dungeons, Raids and Scenarios
1

s3 dot amazonaws dot com/i dot snag dot gy/rZqpd2 dot jpg

How do I get rid of this red box, so I can see mana?

It happens when sac is out, but other classes will show a box for certain abilities too.

EDIT: found it - interface > display aggro highlight unchecked.

2

future reference, you can put links in a preformatted text

https://s3.amazonaws.com/i.snag.gy/rZqpd2.jpg
3

Thank you lol.