Code being reformatted after "remove unused directives in file"

When I choose "Remove unused directives in file" (to remove unused "using"s), a whole heap of other changes are being made to the code, e.g. a header is being added at the start, XML comments and tags are being split onto separate lines, etc.

I've created a Code Cleanup profile with everything unchecked, and selected this new profile in the "Profile to use with silent clean-up" dropdown, but it's still happening. What am I missing?