Usage of libnotify in pastebin plugin hangs

[Jérémy Munsch]

        try
        {
          // yey for breaking API!
          var notification = Object.new (
            typeof (Notify.Notification),
            summary: _("Synapse - Pastebin"),
            body: msg,
            icon_name: "synapse",
            null) as Notify.Notification;
          notification.set_timeout (10);
          notification.show ();
        }
        catch (Error err)
        {
          warning ("%s", err.message);
        }

On kubuntu 15.04, when sending text using pastebin plugin make the desktop manager hangs (plasma).
It freeze few seconds then, randomly, but really few times, the notification will display and the link putted in clipboard as expected.
Other wise it will just not work, after the freeze you may got your selected in clipboard and see no notification.

Removing the notification code make the plug-in work correctly every time, but you will have no notification.