GdkDisplayManager: GdkDisplayManager
Description
Maintains a list of all open   sHierarchy
\link{GObject}
   +----GdkDisplayManagerDetailed Description
The purpose of the GdkDisplayManager singleton object is to offer
notification when displays appear or disappear or the default display 
changes.References
http://developer.gnome.org/doc/API/2.0/gdk/GdkDisplayManager.html