editor background color by scope not working?`

I'd like for test files to have a different background color in the editor. I know the scope is working because the tab is the color I want for test files.

But when I go to Editor/Color Scheme/By Scope and try to set that up I can't get anything scope dependent to work.

I have everything checked in Appearance&Behavior/File Colors although I don't think that is related to my issue. Other than that it does show the scope is working.

PS.

As an aside, I don't think there is any menu alternative or setting to set the editor background picture. You have to use Ctrl-Shift-A to find it. This is no problem for me because I don't plan to use it. But I found it as part of trying to get the editor background colors to work and thought I'd point it out in case it isn't on purpose.