Startup notification identifiers are used by desktop environment to track application startup, to provide user feedback and other features. This function changes the corresponding property on the underlying GdkWindow. Normally, startup identifier is managed automatically and you should only use this function in special cases like transferring focus from other processes. You should use this function before calling Window.present or any equivalent function generating a window map event.
This function is only useful on X11, not with other GTK+ targets.