GtkScrolledWindowが、GtkContainerの subclassになってますが、GtkBinの 
sub classだと思うので one linerです。
--
          yashi


Index: rbgtkcontainer.c
===================================================================
RCS file: /home/cvsroot/ruby/ext/gtk/src/rbgtkcontainer.c,v
retrieving revision 1.1.1.1
diff -u -r1.1.1.1 rbgtkcontainer.c
--- rbgtkcontainer.c	1999/11/17 15:14:23	1.1.1.1
+++ rbgtkcontainer.c	1999/11/24 03:07:14
@@ -759,7 +759,7 @@
 
 void Init_gtk_scrolled_window()
 {
-    gScrolledWin = rb_define_class_under(mGtk, "ScrolledWindow", gContainer);
+    gScrolledWin = rb_define_class_under(mGtk, "ScrolledWindow", gBin);
 
     rb_define_method(gScrolledWin, "initialize", scwin_initialize, -1);
     rb_define_method(gScrolledWin, "set_policy", scwin_set_policy, 2);