Scope only show what's in the mask?

Like it's says in the subject, is it possible to only see in the scopes what is inside a mask? For example, I have a MacBetch chart on the image. I want to isolate one of the grey squares and make it neutral. But the scopes will always show the entire image. I would like to just see an isolated view.

Shift+H will limit the scopes to the masked area.

Whoohoo! Thanks!

Nice tip. Thanks Jack.

You can also temporarily use input PTZR to zoom in to the mask, which will fill the screen and also the scopes.