Vertical/horizontal line to the center of the screen

[Anonymous]

Hello,

I've been getting this extremely annoying cross-like feature that is always showing the center of my screen. I've been trying to figure out how to turn it off for the past couple of hours and it's driving me crazy. For some funny reason it's overlaying only a surface, a fill, or some element directly underneath its path.

Does anyone know what it's called/how to turn it off? It's extremely distracting... I appreciate your help.

Chris