Both. The remove fix for #1693 is trivial, but when testing it, I found out that #1693 currently replaces all linked files with a copy, instead of a new link. Haven't found a way to add a new linked file to a project.
@vweijsters When all your project files are in the same folder, they aren't actually linked files but they are included in multiple projects. In this scenario, simple remove from all and add to all works as users would expect.