Cannot adjust parameters for transparency effect?

There used to be a number here I could change to adjust the transparency, I don’t know how or why but it disappeared one day. I’ve tried resetting my workspace to default, reinstalling, nothing works. What can I do to bring it back?

Nevermind, just fixed it. There’s this little button at the bottom left to hide and unhide parameters. As far as I know there’s no other way to unhide them then this tiny, out of sight, easy avoidable button but… whatever, hopefully this helps somebody in the future.