Grid lines disappear in vanishing point

Question

I can't figure out why sometimes the gridlines will disappear in a plane in vanishing point.  Take the screenshot for instance.  I drew the bottom plane first and gridlines were there.  Then I did an apple-extend on the top grid which has lines.  But now when I click back in the bottom plane, the gridlines don't come back.  Sometimes my gridlines are also red, yellow, or blue and this seems to affect how I can alter them.  What is the pattern?

Answer 1

Found this answer regarding the colors anyway:
"Once you create your perspective plane, it should be represented by a blue grid. Sometimes, however, you may find the color of your grid isn't always be blue—it may be red or yellow. This is Photoshop's way of telling you that you've created an impossible perspective, and the grid needs correction. Yellow means you're close to a proper perspective; red means you're way off."
http://training.sessions.edu/resources/free-tutorials/adobe-photoshop-tutorials/vanishing- point-tutorial.asp