Description GtkMessageDialog presents a dialog with an image representing the type of message (Error, Question, etc.) alongside some message text. It's simply a convenience widget; you could construct the equivalent of GtkMessageDialog from GtkDialog without too much effort, but GtkMessageDialog saves typing. The easiest way to do a modal message dialog is to use gtk_dialog_run(), though you can also pass in the GTK_DIALOG_MODAL flag, gtk_dialog_run() automatically makes the dialog modal and waits for the user to respond to it. gtk_dialog_run() returns when any dialog button is clicked. You might do a non-modal GtkMessageDialog as follows: GtkMessageDialog as GtkBuildable The GtkMessageDialog implementation of the GtkBuildable interface exposes the message area as an internal child with the name "message_area".