Opening sketch leaves IDE window blank and black.

Opening any sketch leaves the IDE window main text area dark and blank. However one line of the sketch is visible in the "slot" above the main IDE window text area and the line can be indexed through the sketch lines with the keyboard up/down arrows.
Never seen this before! What's the fix?

Oops! My bad !

I had moved the green bar at the bottom of the sketch listing all the way up and exposed the compile's window to its maximum extent. Then for no known reason I had evidently scrolled it way over sideways so that all I could see was black screen.

After doing an unneeded IDE reinstall and chasing around the internet (unnecessarily) for a "new" mscvp100.dll, I found my error. It all made for a wasted half day - except for the learning. At least I won't make this dumb mistake again!

Sorry man - I saw this, immediately knew what you did, but then got distracted by my real job and didn't post telling you. Oops.