Doesn't work under 7, although there is a workaround.
It is possible to edit the shortcuts and even add extra ones yourself.
The shortcuts for all users game explorer is in
\ProgramData\Microsoft\Windows\GameExplorer
The shortcuts for current user are in (which is where shortcuts you manually dragged to the Game Explorer will be)
Users\[Username]\AppData\Local\Microsoft\Windows\GameExplorer
In both cases they are in folders with a {GUID} key, but if you open those and then \PlayTasks\0\ there will be a shortcut to the game which is editable.