Changed to check override case before set a charset to msgWindow, bug 28869, r=mscott.

mailnews/mime/src/mimemult.cpp

@@ -224,11 +224,14 @@ MimeMultipart_parse_line (char *line, PRInt32 length, MimeObject *obj)
               {
                 mimeEmitterUpdateCharacterSet(obj->options, cset);
 
-                // Also set this charset to msgWindow
-                if (!nsCRT::strcasecmp(cset, "us-ascii"))
-                  SetMailCharacterSetToMsgWindow(obj, NS_LITERAL_STRING("ISO-8859-1"));
-                else
-                  SetMailCharacterSetToMsgWindow(obj, NS_ConvertASCIItoUCS2(cset));
+                if (!(obj->options->override_charset))
+                {
+                  // Also set this charset to msgWindow
+                  if (!nsCRT::strcasecmp(cset, "us-ascii"))
+                    SetMailCharacterSetToMsgWindow(obj, NS_LITERAL_STRING("ISO-8859-1"));
+                  else
+                    SetMailCharacterSetToMsgWindow(obj, NS_ConvertASCIItoUCS2(cset));
+                }
               }
 
               PR_FREEIF(ct);