diff --git a/screen_sequence_diagrams/add_class.dot b/screen_sequence_diagrams/add_class.dot
index 3f25f2b..0e5b507 100644
--- a/screen_sequence_diagrams/add_class.dot
+++ b/screen_sequence_diagrams/add_class.dot
@@ -15,7 +15,8 @@ digraph G{
 	"SUCCESS"[shape=none];
 	"FAILURE"[shape=none];
 
-	"Controller"[center=true, fillcolor="#aaaaff", style=filled, shape = diamond];
+	"Controller"[center=true, fillcolor="#aaaaff", style=filled, shape = diamond,
+    fixedsize=true, width=1.4, height=1.4];
 	"WhiteListCheck"[center=true, fillcolor="#aaaaff", style=filled, style=filled];
 	"Sidebar Menu" -> "POST";
 	"POST" -> "Controller";