landscape problem

Next happened my friend and i don’t know what he has done but said that some button combination maybe ctrl + something and screenshot about landscape: Screen capture - 3381f3e855446d3720344e0d6501e93c - Gyazo . When push play it looks normal, but in editor view it looks like green or something, is there way to get landscape normally?

This seems a Navmesh.

Remove the navmesh from your world if you not need it.

Hit the P key to turn off navmesh rendering in the viewport.