diff --git a/include/wx/generic/panelg.h b/include/wx/generic/panelg.h
index b7f14c0af2..31a326736e 100644
--- a/include/wx/generic/panelg.h
+++ b/include/wx/generic/panelg.h
@@ -82,7 +82,7 @@ public:
     virtual void InitDialog();
 
 #ifdef __WXUNIVERSAL__
-    virtual bool IsCanvasWindow() { return TRUE; }
+    virtual bool IsCanvasWindow() const { return TRUE; }
     virtual bool ProvidesBackground() { return TRUE; }
 #endif