After updating my Blackberry Q10 to the latest BB10 10.3.1 OS, I noticed an overlay at the bottom left corner of the screen, displaying cpu, memory, fps, events, object, api, draw, triangle, vertex with some random values.
After making some research online, I was able to get the trick to use whenever I want to hide the display. So, I decided to share with you in this blog post.
To hide the display, you have to swipe diagonally from top-left corner to bottom right on the main screen, three times in the direction indicated by the arrow in the screenshot below.
You can enable the overlay if you swipe in same direction too after hiding it.
I hope this helps.