Output limiter

Hi, I’m new to QC I am trying to activate the limiter on outputs 3/4. Although the output levels are active the limiter remains greyed out. I’ve exhausted my little brain so any pointers would be appreciated, Thanks, Wayne.

There’s no control for the limiter. OUT1/2 and OUT 3/4 have one it’s just a hard limiter. It just sorta is there.