When I place a mask, or window I guess it's called, so that I can grade a specific area, the mask wireframe doesn't show up.
I looked through the other posts regarding this topic, and the suggestions from those do not work. Clicking view and toggling Window Outline didn't work. Restarting didn't work. Wasn't really any other suggestions....
Also bring up the Power Window pallet and choose the "Power Window" tool in the Viewer window as Cameron says above.
With a BMD control surface, this should automatically happen when you choose the Power Window mode. I generally choose to only show the visible window on the GUI, because it throws some clients off, but it's a subjective call.