Actually not sure if this is exactly BUG. I encountered this situation by accident in 5.xx or 6.xx versions and I was not sure about the key combination.
I had this situation again while writing code a short time ago, and a strange image appeared.

Maybe it's a surprise egg / easter-egg or a feature for arabic and jewish.
While the editor is open by holding down the CTRL key:

CTRL + > Right justified
CTRL + < Left justified

[Linked Image from img001.prntscr.com]

[Linked Image from img001.prntscr.com]