Photoshop: Insuring that planes work correctly in Vanishing Point

I struggled with making measurements using the Vanishing Point filter. I would draw a plane, but then when I dragged out the measuring tool, there would be no dimensions displayed. I also couldn't drag the corners of the plane. After a lot of phone time with technical support to no avail, I finally figured out that the planes I was defining had parallel sides in the vertical orientation, thus I was describing a plane that wasn't truly in perspective. But lots of architectural renderers like to show architecture with non-converging vertical edges. They should be warned. The documentation should be explicit about what makes a plane work correctly. Better yet, an alert should display when you draw a plane that won't work.