Corrected invalid externalization key references.
diff --git a/plugins/org.eclipse.dltk.python.ui/plugin.properties b/plugins/org.eclipse.dltk.python.ui/plugin.properties
index f31eb7e..e399c8e 100644
--- a/plugins/org.eclipse.dltk.python.ui/plugin.properties
+++ b/plugins/org.eclipse.dltk.python.ui/plugin.properties
@@ -11,6 +11,8 @@
 pluginProvider=Eclipse.org
 pluginName=Dynamic Languages Toolkit Python UI
 
+documentSetupParticipantName=Python Document Setup Participant
+
 PythonPerspective.name = Python
 
 # Context