In Pictures: Windows 8 app shootout - ModernMix v ...
Pinning apps to the desktop taskbar
However, in ModernMix, after you’ve launched an app from the Start Screen, its icon appears on the desktop’s taskbar. You can then pin it like an ordinary Windows desktop application (by right-clicking its icon) so that you can conveniently launch it again from the taskbar whenever you want. Also, you can set the app’s icon onto the desktop itself by right-clicking on its re-sizeable window’s title bar. RetroUI Pro doesn’t display a Windows app that’s running in a re-sizeable window as an icon on the taskbar, so it lacks the function to let you pin it to the taskbar. Nor can you set its icon onto the desktop.
In Pictures: Windows 8 app shootout - ModernMix v RetroUI Pro