Cant spawn more then 3 cars in world editor

When i spawn more then 3 cars in my game (only in world editor) it just stops, all i can do is move the camera and nothing else. Besides going back into the world editor. I cant play my game either.

This is what i am seeing every time, the hud also goes away. I've already tried to uninstall and reinstall my game, and removed all my mods. But it still doesn't work. If someone could help please, i would be very grateful.