It's the same the screensize... the green line normally is seen when you play movies in full screen.
Seems to be all people here have AMD cards, so seems to be this is something affecting AMD cards.
They have changed the code for VLC and did something affecting AMD cards.
I have reported this as a bug, you can also comment there your problems. First you have to register, then log in, and you can comment all you want.
Bug reported here:
https://trac.videolan.org/vlc/ticket/17068#ticket