Collision Editor Not Working

So I'm playing around with the MiniPlat tutorial and am having serious issues with the collision editor. I click the link above the sprite and the editor comes up, but the window where the image should be is solid gray. I can't right click or left click to add new vertices, and theres no collision polygon. I can only see the image after I delete all 4 of the starting coordinate boxes on the right, but I still can't add any vertices. I tried another game and image and its the same thing, and I've also tried uninstalling and reinstalling.

Any help would be greatly appreciated.