I havent opened up truespace in a few weeks, but i believe you need to move your mouse away from the model(or plane in this case) and right click. Instead of the plane being semi transparent, it will go solid again. THATS when your out of mesh edit mode;)
I'm pretty sure that's something I tried. But it's not a big deal right now, I'm moving on through the tutorials. I've got the fish body shaped out. Oddly enough I'm tempted to slap wings on it and call it Bretonian.