Why is there a canvas line on top of my game screen?

My game screen has a part of the canvas on it, it’s just this white line that gets in the way. How do I get rid of this? Here is a picture:

This is likely because gizmos is turned on for the game window

this is an empty scene with just a canvas added and gizmos turned on. Try turning that off at top right of game window and the canvas lines should disappear