By default, after showing the first
GtkWindow, GTK+ calls
gdkNotifyStartupComplete. Call this function to disable
the automatic startup notification. You might do this if your
first window is a splash screen, and you want to delay notification
until after your real main window has been shown, for example.
TRUEto automatically do startup notification
In that example, you would disable startup notification temporarily, show your splash screen, then re-enable it so that showing the main window would automatically result in notification. Since 2.2