So much for these new Stack things being useful - they have a horrid flaw which will really stop me using them. The stack takes on the icons of the contents and does not allow you to change it. Specifically the stack takes on the icon of the first item inside of the folder it is linked to. If you create a Macintosh HD stack this means it carries an Applications folder icon. This is infuriating for me as I previously had two clear things in this section - Macintosh HD and Applications.