Fixed empty menu entries and error output, fix for Issue #2988

Recent Ubuntu's (12.10 and later) give DBusMenuExporterPrivate::addAction errors on adding the same action multiple times. 13.04 does not add the duplicate item to the menu (causing all menus in magics to be empty except one). Fixes Issue  #2988.

IPython/qt/console/mainwindow.py

@@ -647,12 +647,18 b' class MainWindow(QtGui.QMainWindow):'
                 mclass = subdict[name]
                 magic_menu = self._get_magic_menu(mclass)
                 pmagic = prefix + name
+                
+                # Adding seperate QActions is needed for some window managers
                 xaction = QtGui.QAction(pmagic,
                     self,
                     triggered=self._make_dynamic_magic(pmagic)
                     )
+                xaction_all = QtGui.QAction(pmagic,
+                    self,
+                    triggered=self._make_dynamic_magic(pmagic)
+                    )
                 magic_menu.addAction(xaction)
-                self.all_magic_menu.addAction(xaction)
+                self.all_magic_menu.addAction(xaction_all)
 
     def update_all_magic_menu(self):
         """ Update the list of magics in the "All Magics..." Menu