"Largest signal value up" doesn't work in Output

Dear, 

I am using PLAXIS 2D 21.00.01.7. For one of my reports I need to change the Legend Settings/Colouring in the PLAXIS 2D Advanced Output program. However, when I uncheck the "Largest signal value up" box nothing is happening in the Output view. What can be the reason for that? How can I solve it?

Thank you in advance!

Kind regards, 

Mitch Frissen