Custome CSS doesn't seem to be working

I'm trying to remove some sections from the Gravity Forms admin using the Custom CSS section of Ultimate Branding, but it doesn't seem to be working.

For example, I'm adding the following:

.menu {
    display: none;
}

But that menu still shows (it's the section on the right of the Gravity Forms Form Edit screen).

I've also tried using:

.menu {
    display: none !important;
}