Bug#558480:

[Josselin Mouette]

Le samedi 27 novembre 2010 à 15:28 +0100, Roland Baudin a écrit :
> Yes, same problem here. Where are the system sounds in Gnome?
> There is no way to select them and moreover sounds related to user actions
> (click, open drawer, etc.) are completely gone.

You need to install freedesktop-sound-theme.

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