GdkDisplayManager Maintains a list of all open GdkDisplays The purpose of the #GdkDisplayManager singleton object is to offer notification when displays appear or disappear or the default display changes. The GdkDisplayManager struct has no interesting fields. @Since: 2.2 @gdkdisplaymanager: the object which received the signal. @arg1: @void: @Returns: @display_manager: @Returns: @display_manager: @display: @display_manager: @Returns: @display: @Returns: