--- libwnck/tasklist.c.orig	2009-04-19 19:40:32.000000000 +0200
+++ libwnck/tasklist.c	2009-08-30 15:21:07.125772597 +0200
@@ -3371,7 +3371,9 @@
   text = wnck_task_get_text (task, FALSE, FALSE);
   /* if text is NULL, this unsets the tooltip, which is probably what we'd want
    * to do */
-  gtk_widget_set_tooltip_text (task->button, text);
+  /* the following line has been commented to disable persistent tooltips 
+   * when switching from an application to another */
+/*  gtk_widget_set_tooltip_text (task->button, text); */
   g_free (text);
 
   gtk_widget_queue_resize (GTK_WIDGET (task->tasklist));