diff --git a/include/wx/msw/bitmap.h b/include/wx/msw/bitmap.h
index a79d497587..c677af8ca3 100644
--- a/include/wx/msw/bitmap.h
+++ b/include/wx/msw/bitmap.h
@@ -171,6 +171,7 @@ public:
     // disappear in the future
     bool HasAlpha() const;
     void UseAlpha();
+    void ResetAlpha();
 
     // support for scaled bitmaps
     virtual double GetScaleFactor() const { return 1.0; }
diff --git a/src/msw/bitmap.cpp b/src/msw/bitmap.cpp
index be45716e64..44a236defa 100644
--- a/src/msw/bitmap.cpp
+++ b/src/msw/bitmap.cpp
@@ -1241,6 +1241,12 @@ void wxBitmap::UseAlpha()
         GetBitmapData()->m_hasAlpha = true;
 }
 
+void wxBitmap::ResetAlpha()
+{
+    if ( GetBitmapData() )
+        GetBitmapData()->m_hasAlpha = false;
+}
+
 bool wxBitmap::HasAlpha() const
 {
     return GetBitmapData() && GetBitmapData()->m_hasAlpha;