diff --git a/ChangeLog b/ChangeLog
index 28e86a6267..59a7fd004f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,11 @@
 2005-03-30  Matthias Clasen  <mclasen@redhat.com>
 
+	* gtk/gtkclipboard.c (gtk_clipboard_set_can_store): 
+	Don't accept n_targets == -1.
+	(clipboard_unset): unref the old_data, not the
+	user_data which we have just cleared.  (#172038, Sven
+	Neumann)
+
 	* gtk/gtkcombobox.c (gtk_combo_box_popup): Don't 
 	segfault if somebody tries to popup an unrealized
 	combo box.  (#172031, Felipe Heidrich)
diff --git a/ChangeLog.pre-2-10 b/ChangeLog.pre-2-10
index 28e86a6267..59a7fd004f 100644
--- a/ChangeLog.pre-2-10
+++ b/ChangeLog.pre-2-10
@@ -1,5 +1,11 @@
 2005-03-30  Matthias Clasen  <mclasen@redhat.com>
 
+	* gtk/gtkclipboard.c (gtk_clipboard_set_can_store): 
+	Don't accept n_targets == -1.
+	(clipboard_unset): unref the old_data, not the
+	user_data which we have just cleared.  (#172038, Sven
+	Neumann)
+
 	* gtk/gtkcombobox.c (gtk_combo_box_popup): Don't 
 	segfault if somebody tries to popup an unrealized
 	combo box.  (#172031, Felipe Heidrich)
diff --git a/ChangeLog.pre-2-8 b/ChangeLog.pre-2-8
index 28e86a6267..59a7fd004f 100644
--- a/ChangeLog.pre-2-8
+++ b/ChangeLog.pre-2-8
@@ -1,5 +1,11 @@
 2005-03-30  Matthias Clasen  <mclasen@redhat.com>
 
+	* gtk/gtkclipboard.c (gtk_clipboard_set_can_store): 
+	Don't accept n_targets == -1.
+	(clipboard_unset): unref the old_data, not the
+	user_data which we have just cleared.  (#172038, Sven
+	Neumann)
+
 	* gtk/gtkcombobox.c (gtk_combo_box_popup): Don't 
 	segfault if somebody tries to popup an unrealized
 	combo box.  (#172031, Felipe Heidrich)
diff --git a/gtk/gtkclipboard.c b/gtk/gtkclipboard.c
index bb21b009c7..dde348e1cd 100644
--- a/gtk/gtkclipboard.c
+++ b/gtk/gtkclipboard.c
@@ -678,7 +678,7 @@ clipboard_unset (GtkClipboard *clipboard)
    */
   if (old_have_owner &&
       old_n_storable_targets != -1)
-    g_object_unref (clipboard->user_data);
+    g_object_unref (old_data);
 }
 
 /**
@@ -1609,6 +1609,7 @@ gtk_clipboard_set_can_store (GtkClipboard         *clipboard,
   };
   
   g_return_if_fail (GTK_IS_CLIPBOARD (clipboard));
+  g_return_if_fail (n_targets >= 0);
 
   if (clipboard->selection != GDK_SELECTION_CLIPBOARD)
     return;