diff --git a/src/mgl/region.cpp b/src/mgl/region.cpp
index f2778ffa99..1211a7a954 100644
--- a/src/mgl/region.cpp
+++ b/src/mgl/region.cpp
@@ -127,7 +127,7 @@ void wxRegion::Clear()
 // Information on region
 //-----------------------------------------------------------------------------
 
-bool wxRegion::DoIsEqual(const wxRegion& region) const
+bool wxRegion::DoIsEqual(const wxRegion& WXUNUSED(region)) const
 {
     wxFAIL_MSG( _T("not implemented") );