How can I disable automatic adding of @script JScript directive?

I am converting several of my JScript button functions to Standard Functions. When I choose Standard Function from the Type: dropdown, the @script JScript directive is added as the first line in the command editor, even though there is no Jscript present.

How can I prevent automatically inserting the @script JScript directive in the command editor?

The @script line is already there, it's just hidden from view when the editor is in Script mode. Changing the mode back to standard function reveals that and any other hidden lines.