This policy setting allows you to specify how long a user's RemoteApp session will remain in a disconnected state after closing all RemoteApp programs before the session is logged off from the RD Session Host server.By default if a user closes a RemoteApp program the session is disconnected from the RD Session Host server but it is not logged off.If you enable this policy setting when a user closes the last running RemoteApp program associated with a session the RemoteApp session will remain in a disconnected state until the time limit that you specify is reached. When the time limit specified is reached the RemoteApp session will be logged off from the RD Session Host server. If the user starts a RemoteApp program before the time limit is reached the user will reconnect to the disconnected session on the RD Session Host server.If you disable or do not configure this policy setting when a user closes the last RemoteApp program the session will be disconnected from the RD Session Host server but it is not logged off.Note: This policy setting appears in both Computer Configuration and User Configuration. If both policy settings are configured the Computer Configuration policy setting takes precedence.
Windows Components\Remote Desktop Services\Remote Desktop Session Host\Session Time Limits
User
At least Windows Server 2008
HKCU\SOFTWARE\Policies\Microsoft\Windows NT\Terminal Services!RemoteAppLogoffTimeLimit
Terminalserver-Server.admx