Ctrl+N inserts a character sketch?

Hey all.

In just one of my projects, when I hit ctrl+N (or add a new text documents using the button), instead of inserting a blank text document, it inserts a character sketch from elsewhere in the project.

It does this no matter where in the project I try to add a new text document. It always inserts the same character sketch.

I’m guessing I must have accidentally set that character sketch as the default text document for the project somehow, but I don’t know how I did that. More importantly, I don’t know how to undo it. Any help would be appreciated!