ignore the code » The Pitfalls of Switching

Not all icons in the Finder are created equal. There are the normal file and folder icons. Then there are disk icons, which appear in the same context as normal icons, but behave differently. Then there are the proxy icons in window title bars. Then there are the quasi-alias icons in the Dock or the Finder sidebar - but even among the Finder sidebar icons, there are differences. These non-obvious inconsistencies are confusing to new users