diff --git a/rtgui/toolpanel.h b/rtgui/toolpanel.h
index d5814c040..d3d7439a9 100644
--- a/rtgui/toolpanel.h
+++ b/rtgui/toolpanel.h
@@ -88,7 +88,7 @@ public:
     {
         multiImage = m;
     }
-    void           setListener     (ToolPanelListener* tpl)
+    virtual void           setListener     (ToolPanelListener* tpl)
     {
         listener = tpl;
     }