subr.el (remove-yank-excluded-properties): Explain in a comment why `category'

 property is removed.

2 files changed, 10 insertions, 1 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 5d2c0d87b03..5613793edff 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,8 @@
+2010-02-20  Eli Zaretskii  <eliz@gnu.org>
+
+        * subr.el (remove-yank-excluded-properties): Explain in a comment
+        why `category' property is removed.
+
 2010-02-19  Chong Yidong  <cyd@stupidchicken.com>
 
         * isearch.el (isearch-update-post-hook, isearch-update): Revert
diff --git a/lisp/subr.el b/lisp/subr.el
index d2363099b7c..977d5a53f35 100644
--- a/lisp/subr.el
+++ b/lisp/subr.el
@@ -2442,7 +2442,11 @@ Otherwise, return nil."
   "Remove `yank-excluded-properties' between START and END positions.
 Replaces `category' properties with their defined properties."
   (let ((inhibit-read-only t))
-    ;; Replace any `category' property with the properties it stands for.
+    ;; Replace any `category' property with the properties it stands
+    ;; for.  This is to remove `mouse-face' properties that are placed
+    ;; on categories in *Help* buffers' buttons.  See
+    ;; http://lists.gnu.org/archive/html/emacs-devel/2002-04/msg00648.html
+    ;; for the details.
     (unless (memq yank-excluded-properties '(t nil))
       (save-excursion
         (goto-char start)