Per fdo icon spec and http://fedoraproject.org/wiki/ScriptletSnippets (Gtk+ Icon cache), something like the following should be added: %post for icon_theme in crystalsvg hicolor ; do touch --no-create %{_datadir}/icons/${icon_theme} ||: gtk-update-icon-cache -q %{_datadir}/icons/${icon_theme} 2> /dev/null ||: done update-desktop-database %{_datadir}/applications > /dev/null 2>&1 || : %postun for icon_theme in crystalsvg hicolor ; do touch --no-create %{_datadir}/icons/${icon_theme} ||: gtk-update-icon-cache -q %{_datadir}/icons/${icon_theme} 2> /dev/null ||: done And while we're on the topic, wouldn't hurt to add update-desktop-database %{_datadir}/applications > /dev/null 2>&1 || : to both %post/%postun to register kdelibs' apps that contain MimeType= in their .desktop files.
Upon closer inspection, kdelibs doesn't put anything in hicolor/ so references to it should be omitted, ie, use <code> for icon_theme in crystalsvg ; do </code> instead.
it's now fixed in CVS, it will be included in next rebuild. Thanks for your report.