GTK+ Warning: Can't set a parent on widget which has a parent!!

[Phong Cao <phngcv gmail com>]

Hello everybody,

I am trying to write the interface for my music manager using GTK+. The
program was compiled successfully. However, when I executed it, the machine
returned errors:

(dingo_draft:6462): Gtk-WARNING **: Can't set a parent on widget which
has a parent(dingo_draft:6462): Gtk-CRITICAL **: gtk_widget_realize:
assertion `GTK_WIDGET_ANCHORED (widget) || GTK_IS_INVISIBLE (widget)'
failed**Gtk:ERROR:/build/buildd/gtk+2.0-2.20.1/gtk/gtkwidget.c:8760:gtk_widget_real_map:
assertion failed: (gtk_widget_get_realized (widget))Aborted

Attached with this email is the source code of the program. Please note that
this is *just the interface written in GTK+*. I did not add any signals in
yet. I think there might be some problems with the GTK+ functions, but I
could not locate where the errors occured.

Thank you for helping me with this problem!! Hope you guys have a good
weekend!