From 5630f4e6acba6359d7d182de034a6af563025df9 Mon Sep 17 00:00:00 2001
From: Botond Beres <botondus@gmail.com>
Date: Fri, 27 Oct 2017 16:23:40 +0100
Subject: [PATCH] [2.0.x] Fixed #28205 -- Doc'd that
 ModelAdmin.prepopulated_fields only works on add forms.

Backport of 56b364bacca0d6a6cd8fbcd93aeb49f3ad46e58c from master
---
 docs/ref/contrib/admin/index.txt | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/docs/ref/contrib/admin/index.txt b/docs/ref/contrib/admin/index.txt
index adbd18ef74b..8f729bee62e 100644
--- a/docs/ref/contrib/admin/index.txt
+++ b/docs/ref/contrib/admin/index.txt
@@ -1048,6 +1048,10 @@ subclass::
     of the source fields, and then by transforming that result into a valid
     slug (e.g. substituting dashes for spaces).
 
+    Fields are prepopulated on add forms but not on change forms. It's usually
+    undesired that slugs change after an object is created (which would cause
+    an object's URL to change if the slug is used in it).
+
     ``prepopulated_fields`` doesn't accept ``DateTimeField``, ``ForeignKey``,
     ``OneToOneField``, and ``ManyToManyField`` fields.