the xfce4-panel plugins use desktop files, it seems with the last dapper version 4.3.30svn+r20393, xfce4-panel is not considering those files.
Add items dialof shows only the plugins installed with the panel
the xfce4-panel plugins use desktop files, it seems with the last dapper version 4.3.30svn+r20393, xfce4-panel is not considering those files.
Add items dialof shows only the plugins installed with the panel