MixConvert v6 and LRC

I have a LRC track in a stereo mix.
I want to listen to the sides only for a large stereo ambiance or or get more center to focus it.
In the MixConvert v6 I have 3 sliders “center” “side” global gain"
I would assume to listen only to the stereo mics i would put center at -inf
to get a mono version I would put side to -inf
and global gain would only level the mix of center + side. But it doesn’t look that way.
If I put center and side at -inf but global gain at 0 I still here it all… how that work ? no info I can use on the manual.