diff --git a/include/wx/propgrid/propgrid.h b/include/wx/propgrid/propgrid.h
index d40f249aae..b01d995dc7 100644
--- a/include/wx/propgrid/propgrid.h
+++ b/include/wx/propgrid/propgrid.h
@@ -1553,12 +1553,12 @@ public:
     // Converts escape sequences in src_str to newlines,
     // tabs, etc. and copies result to dst_str.
     static wxString& ExpandEscapeSequences( wxString& dst_str,
-                                            wxString& src_str );
+                                            const wxString& src_str );
 
     // Converts newlines, tabs, etc. in src_str to escape
     // sequences, and copies result to dst_str.
     static wxString& CreateEscapeSequences( wxString& dst_str,
-                                            wxString& src_str );
+                                            const wxString& src_str );
 
     // Checks system screen design used for laying out various dialogs.
     static bool IsSmallScreen();
diff --git a/src/propgrid/propgrid.cpp b/src/propgrid/propgrid.cpp
index 345300e09d..240a7f1be2 100644
--- a/src/propgrid/propgrid.cpp
+++ b/src/propgrid/propgrid.cpp
@@ -1733,7 +1733,7 @@ wxPoint wxPropertyGrid::GetGoodEditorDialogPosition( wxPGProperty* p,
 
 // -----------------------------------------------------------------------
 
-wxString& wxPropertyGrid::ExpandEscapeSequences( wxString& dst_str, wxString& src_str )
+wxString& wxPropertyGrid::ExpandEscapeSequences( wxString& dst_str, const wxString& src_str )
 {
     dst_str.clear();
 
@@ -1791,7 +1791,7 @@ wxString& wxPropertyGrid::ExpandEscapeSequences( wxString& dst_str, wxString& sr
 
 // -----------------------------------------------------------------------
 
-wxString& wxPropertyGrid::CreateEscapeSequences( wxString& dst_str, wxString& src_str )
+wxString& wxPropertyGrid::CreateEscapeSequences( wxString& dst_str, const wxString& src_str )
 {
     dst_str.clear();