If the 'thunar' USE flag is enabled for xfce-base/xfdesktop, but you then happen to build xfce-base/thunar _without_ the 'dbus' USE flag, xfdesktop's integration with Thunar becomes non-functional. I get this error whenever I double-click one of my desktop icons: "The folder could not be opened" - "The name org.xfce.FileManager was not provided by any .services files" xfdesktop might as well depend on 'thunar[dbus]' if the 'thunar' USE flag is set, since it isn't very useful if thunar is built without dbus support.
These are my USE flag settings for xfce-base/{xfdesktop,thunar}: xfce-base/xfdesktop-4.8.1: libnotify thunar -debug xfce-base/thunar-1.2.3: exif libnotify pcre startup-notification -dbus -debug -test -udev -xfce_plugins_trash
Yes, you are right. + 29 Oct 2011; Samuli Suominen <ssuominen@gentoo.org> xfdesktop-4.8.1.ebuild, + xfdesktop-4.8.3.ebuild: + Missing USE="dbus" depend for Thunar integration wrt #388407 by Dean Matzkov Fixed in tree.