opening editor in new window don't work

When I try to use editor in a new window, the buttom don’t do anything… What can I do?
It was working, but stoped in the last 2 days…!

I am using the last version 10.5.20 build 179
MacBook pro mid 2015 - Catalina 10.15.5

Hi and welcome,

Could you try in Cubase Safe Start Mode [Disable preferences], please?