diff --git a/data/themes/default.cfg b/data/themes/default.cfg
index 4f82992ecac..a851f13f805 100644
--- a/data/themes/default.cfg
+++ b/data/themes/default.cfg
@@ -1,4 +1,7 @@
 #textdomain wesnoth
+
+# some information about how theming works (especially the coordinates defined with rect=):
+# http://www.wesnoth.org/forum/viewtopic.php?p=213708#213708
 [theme]
     name=null
     [resolution]