--- a/widget/gtk/nsClipboard.cpp
+++ b/widget/gtk/nsClipboard.cpp
@@ -241,17 +241,18 @@ nsClipboard::SetData(nsITransferable *aT
     
     // Get GTK clipboard (CLIPBOARD or PRIMARY)
     GtkClipboard *gtkClipboard = gtk_clipboard_get(GetSelectionAtom(aWhichClipboard));
   
     gint numTargets;
     GtkTargetEntry *gtkTargets = gtk_target_table_new_from_list(list, &numTargets);
           
     // Set getcallback and request to store data after an application exit
-    if (gtk_clipboard_set_with_data(gtkClipboard, gtkTargets, numTargets, 
+    if (gtkTargets &&
+        gtk_clipboard_set_with_data(gtkClipboard, gtkTargets, numTargets,
                                     clipboard_get_cb, clipboard_clear_cb, this))
     {
         // We managed to set-up the clipboard so update internal state
         // We have to set it now because gtk_clipboard_set_with_data() calls clipboard_clear_cb()
         // which reset our internal state 
         if (aWhichClipboard == kSelectionClipboard) {
             mSelectionOwner = aOwner;
             mSelectionTransferable = aTransferable;