diff --git a/gtk2_ardour/button_joiner.cc b/gtk2_ardour/button_joiner.cc
index 0c60cba1db..8671dab9ab 100644
--- a/gtk2_ardour/button_joiner.cc
+++ b/gtk2_ardour/button_joiner.cc
@@ -99,7 +99,7 @@ ButtonJoiner::~ButtonJoiner ()
 }
 
 void
-ButtonJoiner::render (cairo_t* cr, cairo_rectangle_t*)
+ButtonJoiner::render (cairo_t* cr)
 {
 	double h = get_height();