diff --git a/contrib/include/wx/gizmos/splittree.h b/contrib/include/wx/gizmos/splittree.h
index 2e9dd678ec..45eec69af9 100644
--- a/contrib/include/wx/gizmos/splittree.h
+++ b/contrib/include/wx/gizmos/splittree.h
@@ -87,6 +87,8 @@ public:
                                int range,
                                bool update);
 
+    // Override to get scroll values from companion window
+    virtual void DoCalcScrolledPosition(int x, int y, int *xx, int *yy) const;
 //// Helpers
     void HideVScrollbar();