diff --git a/collects/scribblings/gui/style-list-class.scrbl b/collects/scribblings/gui/style-list-class.scrbl
index 7a05a1753d..440b711eb1 100644
--- a/collects/scribblings/gui/style-list-class.scrbl
+++ b/collects/scribblings/gui/style-list-class.scrbl
@@ -126,7 +126,8 @@ The @scheme[like-style] style must be in this style list, otherwise
 @defmethod[(notify-on-change [f ((or/c (is-a?/c style<%>) #f) . -> . any)])
            any/c]{
 
-Attaches a callback to the style list. The callback is invoked
+Attaches a callback to the style list, retaining the callback only weakly (in
+ the sense of @racket[make-weak-box]). The callback is invoked
  whenever a style is modified.
 
 Often, a change in one style will trigger a change in several other