Unwanted Split-Screen in Render Window

[Michael J. Brown]

SO, I've been working on this scene and running renders from it all day with no issues.  That is until just now when I noticed a 'split-screen' happening in my render window.  I must have hit a bad combination of keys somewhere along the way that triggered this.  I've never encountered this before.  (light cache pre-render attached)

 

I've combed through my Render Setup and found nothing out of the ordinary.  Does anyone know how I can disable it?

[Michael J. Brown]

SOLUTION: It was a Stereoscopic object that got added into the scene.  Some combination of keys I pressed obviously created it.  I deleted it, and voila!  Problem fixed.