Gnome provides utility functions for relaying simple messages to
the user and asking simple questions. The utility functions
serve two purposes: first, they keep programmers from writing
dozens of identical dialogs; second, they let the user choose
whether messages should appear in dialogs or on the appbar. The
main set of utility functions assume that your app uses the
GnomeApp widget, and that one is visible at the
time they're called. These functions have a dialog backend and
an appbar backend. The dialog backend is exposed, so you can use
it directly if you have no GnomeApp widget available. The
GnomeApp functions do not
assume you have an appbar available; you should use them even if
your app has no appbar. In some cases it makes a difference (for
example, dialog can be positioned relative to the
GnomeApp).