This fixes a problem of overaggressively grouping windows in the
tasklist with our default size 24 panel.  See bnc #148840 for
details and a screenshot.

Index: libwnck/tasklist.c
===================================================================
--- libwnck/tasklist.c.orig
+++ libwnck/tasklist.c
@@ -216,6 +216,9 @@ struct _WnckTasklistPrivate
   int *size_hints;
   int size_hints_len;
 
+  gint last_width;
+  gint last_height;
+
   WnckLoadIconFunction icon_loader;
   void *icon_loader_data;
   GDestroyNotify free_icon_loader_data;
@@ -692,6 +695,9 @@ wnck_tasklist_init (WnckTasklist *taskli
   for (i = 0; i < N_SCREEN_CONNECTIONS; i++)
     tasklist->priv->screen_connections[i] = 0;
 
+  tasklist->priv->last_width = -1;
+  tasklist->priv->last_height = -1;
+
   tasklist->priv->idle_callback_tag = 0;
 
   tasklist->priv->size_hints = NULL;
@@ -1324,8 +1330,16 @@ wnck_tasklist_size_request  (GtkWidget  
   tasklist->priv->max_button_width = wnck_tasklist_get_button_size (widget);
   tasklist->priv->max_button_height = max_height;
 
-  fake_allocation.width = GTK_WIDGET (tasklist)->allocation.width;
-  fake_allocation.height = GTK_WIDGET (tasklist)->allocation.height;
+  /* fake_allocation.width = GTK_WIDGET (tasklist)->allocation.width;
+     fake_allocation.height = GTK_WIDGET (tasklist)->allocation.height; */
+  if (tasklist->priv->last_width != -1)
+      fake_allocation.width = tasklist->priv->last_width;
+  else
+      fake_allocation.width = GTK_WIDGET (tasklist)->allocation.width;
+  if (tasklist->priv->last_height != -1)
+      fake_allocation.height = tasklist->priv->last_height;
+  else
+      fake_allocation.height = GTK_WIDGET (tasklist)->allocation.height;
 
   array = g_array_new (FALSE, FALSE, sizeof (int));
 
@@ -1501,6 +1515,9 @@ wnck_tasklist_size_allocate (GtkWidget  
   
   tasklist = WNCK_TASKLIST (widget);
 
+  tasklist->priv->last_width = allocation->width;
+  tasklist->priv->last_height = allocation->height;
+
   n_windows = g_list_length (tasklist->priv->windows);
   n_startup_sequences = g_list_length (tasklist->priv->startup_sequences);
   n_grouped_buttons = 0;