Copying a form with submit button causes confluence to open inside itself

Description:

Form submission button opens new confluence window inside editor

Steps to reproduce:

1. Install source editor in confluence instance
2. paste the following into a source editor

    <form>
   <input type="submit" value="Go!" />
   </form>

3. Hit the button and see that a new Confluence window is opened

4. If you hit e you open the editor again and are able to continue to add windows

Expected result:

Nothing

Actual Result:

open new Confluence window