Windowck title plugin crash with visible on desktop enabled

The plugin crashes when switching to Desktop "Show the plugin on desktop." is enabled.

Possible fix:

diff --git a/panel-plugin/title/wcktitle-title.c b/panel-plugin/title/wcktitle-title.c
index f4a71ef..14e2192 100644
--- a/panel-plugin/title/wcktitle-title.c
+++ b/panel-plugin/title/wcktitle-title.c
@@ -52,6 +52,10 @@ static gboolean is_window_on_active_workspace_and_no_other_maximized_windows_abo
         return FALSE;
     }
 
+    if(window_is_desktop (window)) {
+        return TRUE;
+    }
+
     windows = wnck_screen_get_windows_stacked(screen);
     top_window = g_list_last(windows);
     bottom_window = g_list_first(windows);