I was wondering the same thing and landed on your post. I had three content tabs open in Light Table view. Two of them displayed as expected, one did not.
What worked: right-mouse click on the "Content" tab and made sure "Vertical Layout" was selected.
The Horizontal Layout is exclusively set to allow the FilmStrip view to function. It is selectable so that if you make a new Workplace that requires the FilmStrip view, you have it available to select it.