Can't change Max/Min values of note expression

Hi, I am currently using Cubase pro 11.
as shown in the title, the Max/Min values in the parameter details section set in the note expression section of inspector, are greyed out and can’t change those values.
How can I activate them? or is there any other manners to change them?
I could not find in the operation manual.

I created an account for this question and I am new here.
So, sorry if I’m misunderstanding the usage of this forum.