Script Being removed

Hello so for some reason suddenly this black thing has come on and when I type it removes everything I type. I am not sure why as I have not changed any colors and it only happens on this one script.

press the “insert” button on your keyboard and it will go away

What insert button??? I have not ever heard of this before.

It is to the right of your keyboard. It is right above the 4 arrows.

Thanks for the help :slight_smile: