The ::realize signal is emitted when @widget is associated with a #GdkWindow, which means that gtk_widget_realize() has been called or the widget has been mapped (that is, it is going to be drawn).
See Implementation
The ::realize signal is emitted when @widget is associated with a #GdkWindow, which means that gtk_widget_realize() has been called or the widget has been mapped (that is, it is going to be drawn).