diff --git a/interface/wx/colour.h b/interface/wx/colour.h
index a4771ec582..c6f0bf122d 100644
--- a/interface/wx/colour.h
+++ b/interface/wx/colour.h
@@ -268,6 +268,7 @@ public:
 /** @name Predefined colors. */
 //@{
 wxColour wxNullColour;
+wxColour wxTransparentColour;
 wxColour* wxBLACK;
 wxColour* wxBLUE;
 wxColour* wxCYAN;