Creates the GDK resources associated with a widget.
Normally realization happens implicitly; if you show a widget and all its parent containers, then the widget will be realized and mapped automatically.
Realizing a widget requires all the widget’s parent widgets to be
realized; calling this function realizes the widget’s parents
in addition to
widget itself. If a widget is not yet inside a
toplevel window when you realize it, bad things will happen.
This function is primarily used in widget implementations, and
isn’t very useful otherwise. Many times when you think you might
need it, a better approach is to connect to a signal that will be
called after the widget is realized automatically, such as