diff --git a/ext/tk/MANIFEST b/ext/tk/MANIFEST
index 28a9e23ee2..0f3a87b488 100644
--- a/ext/tk/MANIFEST
+++ b/ext/tk/MANIFEST
@@ -197,6 +197,7 @@ lib/tkextlib/tcllib/autoscroll.rb
 lib/tkextlib/tcllib/ctext.rb
 lib/tkextlib/tcllib/cursor.rb
 lib/tkextlib/tcllib/datefield.rb
+lib/tkextlib/tcllib/ico.rb
 lib/tkextlib/tcllib/ip_entry.rb
 lib/tkextlib/tcllib/plotchart.rb
 lib/tkextlib/tcllib/setup.rb