If you enable this setting the "Undock PC" button is removed from the simple Start Menu and your PC cannot be undocked.If you disable this setting or do not configure it the "Undock PC" button remains on the simple Start menu and your PC can be undocked.
Policy path:
Start Menu and Taskbar
Scope:
User
Supported on:
At least Windows Server 2003 operating systems or Windows XP Professional
Registry settings:
HKCU\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer!NoStartMenuEjectPC
Filename:
StartMenu.admx