--- a/doodle/tk/palette.d	Tue Aug 10 22:55:54 2010 +0930
+++ b/doodle/tk/palette.d	Wed Aug 11 15:07:58 2010 +0930
@@ -2,14 +2,16 @@
 
 // XXX Not sure whether to use delegates or observer pattern...
 
-interface IPalette {
+interface IPalette(T) {
     struct Item {
         string iconPath;
         string labelText;
         string tooltipText;
-        void delegate(int) callback;
-    }
+        T t;
+    };
 
-    void configure(in Item[] items);
-    void activate(in int index);
+    alias void delegate(T) Callback;
+
+    void configure(Item[] items, Callback callback);
+    void activate(T t);
 }