Question
What is this "slider" next to a mask switch?
I am using Lightroom 8.4.1. and there is this slider sort of thing next to a mask toggle switch... I have tried to figure out what is it and does it actually do anything? I cannot seem to find what is the use of it, if there is any? I can't use it as a slider, so is the whole O------- thing basically a switch? Thanks for help!

