What Happened to My Views?

So, I'm happily working in the following scenario:
I have my screen split in half horizontally, Track view on top, and Piano view tiled with Markers View on the bottom half.  I'm typing in my chords in the Markers tab, when all of a sudden that view (for NO REASON AT ALL) just expands and takes up the entire screen.  I played around with it for a solid 30 mins, while cursing Cakewalk developers, and never could see under ANY menu how to make it go back to the way I had it.  I saved it as another name, and my old file name still works just fine, but I want to know WTH happened.  I've seen this kind of inexplicable change happen ALL THE TIME when I press "G" to goto a particular location, and all of a sudden it shows a completely different Screenshot.  I KNOW that's a glitch.  No illusion AT ALL.
 
So, how do I get the panes working correctly again?
KC