diff --git a/include/wx/defs.h b/include/wx/defs.h
index 0a16399ebf..22eeaba4a6 100644
--- a/include/wx/defs.h
+++ b/include/wx/defs.h
@@ -605,6 +605,7 @@ typedef void (*wxFunction) (wxObject&, wxEvent&);
 #define wxSP_NOBORDER       0x0000
 #define wxSP_3D             0x0004
 #define wxSP_BORDER         0x0008
+#define wxSP_PERMIT_UNSPLIT 0x0010
 
 /*
  * wxFrame extra flags
diff --git a/include/wx/event.h b/include/wx/event.h
index fc04af3fba..e9f8825d9f 100644
--- a/include/wx/event.h
+++ b/include/wx/event.h
@@ -220,8 +220,9 @@ const wxEventType wxEVT_COMMAND_NOTEBOOK_PAGE_CHANGING =    wxEVT_FIRST + 803;
 
 /* Splitter events */
 const wxEventType wxEVT_COMMAND_SPLITTER_SASH_POS_CHANGED = wxEVT_FIRST + 850;
-const wxEventType wxEVT_COMMAND_SPLITTER_DOUBLECLICKED = wxEVT_FIRST + 851;
-const wxEventType wxEVT_COMMAND_SPLITTER_UNSPLIT = wxEVT_FIRST + 852;
+const wxEventType wxEVT_COMMAND_SPLITTER_SASH_POS_CHANGING = wxEVT_FIRST + 851;
+const wxEventType wxEVT_COMMAND_SPLITTER_DOUBLECLICKED = wxEVT_FIRST + 852;
+const wxEventType wxEVT_COMMAND_SPLITTER_UNSPLIT = wxEVT_FIRST + 853;
 
 const wxEventType wxEVT_USER_FIRST =                        wxEVT_FIRST + 2000;