diff --git a/swad_changelog.h b/swad_changelog.h
index 0941108bf..e1b755287 100644
--- a/swad_changelog.h
+++ b/swad_changelog.h
@@ -136,13 +136,15 @@
 /****************************** Public constants *****************************/
 /*****************************************************************************/
 
-#define Log_PLATFORM_VERSION	"SWAD 15.241.2 (2016-07-04)"
+#define Log_PLATFORM_VERSION	"SWAD 15.241.3 (2016-07-04)"
 #define CSS_FILE		"swad15.229.css"
 #define JS_FILE			"swad15.238.1.js"
 
 // Number of lines (includes comments but not blank lines) has been got with the following command:
 // nl swad*.c swad*.h css/swad*.css py/swad*.py js/swad*.js soap/swad*.h sql/swad*.sql | tail -1
 /*
+        Version 15.241.3: Jul 04, 2015	Changes in layout of form to compose message.
+					Code optimization in list of selected users. (203628 lines)
         Version 15.241.2: Jul 04, 2015	Changes in layout of form to compose message. (203619 lines)
         Version 15.241.1: Jul 04, 2015	Code refactoring related with forms submit. (203620 lines)
         Version 15.241:   Jul 04, 2015	When composing a new message, subject and content are shown even if list of users is too big, in order to keep messages that had begun to be written. (203618 lines)
diff --git a/swad_message.c b/swad_message.c
index e9176da2c..161befeef 100644
--- a/swad_message.c
+++ b/swad_message.c
@@ -171,6 +171,9 @@ static void Msg_PutFormMsgUsrs (char *Content)
    char YN[1+1];
    unsigned NumTotalUsrs = 0;
    bool ShowUsers = true;
+   bool GetListUsrs = !Gbl.Msg.ShowOnlyOneRecipient &&		// Show list of potential recipients
+	              (Gbl.Usrs.Me.IBelongToCurrentCrs ||	// If there is a course selected and I belong to it
+	               Gbl.Usrs.Me.LoggedRole == Rol_SYS_ADM);
 
    Gbl.Usrs.LstUsrs[Rol_TEACHER].NumUsrs =
    Gbl.Usrs.LstUsrs[Rol_STUDENT].NumUsrs = 0;
@@ -191,35 +194,8 @@ static void Msg_PutFormMsgUsrs (char *Content)
       Par_GetParToText ("ShowOnlyOneRecipient",YN,1);
       Gbl.Msg.ShowOnlyOneRecipient = (Str_ConvertToUpperLetter (YN[0]) == 'Y');
      }
-
-   /***** Get list of users' IDs or nicknames written explicitely *****/
-   Usr_GetListMsgRecipientsWrittenExplicitelyBySender (false);
-
-   /***** Get who to show as potential recipients:
-          - only the selected recipient
-          - any user (default) *****/
-   Par_GetParToText ("ShowOnlyOneRecipient",YN,1);
-   Gbl.Msg.ShowOnlyOneRecipient = (Str_ConvertToUpperLetter (YN[0]) == 'Y');
-
-   /***** Get list of users belonging to the current course *****/
-   if (!Gbl.Msg.ShowOnlyOneRecipient &&		// Show list of potential recipients
-       (Gbl.Usrs.Me.IBelongToCurrentCrs ||	// If there is a course selected and I belong to it
-        Gbl.Usrs.Me.LoggedRole == Rol_SYS_ADM))
-     {
-      /***** Get and update type of list,
-	     number of columns in class photo
-	     and preference about view photos *****/
-      Usr_GetAndUpdatePrefsAboutUsrList ();
-
-      /***** Form to select groups *****/
-      Grp_ShowFormToSelectSeveralGroups (ActReqMsgUsr);
-
-      /***** Get and order lists of users from this course *****/
-      Usr_GetListUsrs (Rol_TEACHER,Sco_SCOPE_CRS);
-      Usr_GetListUsrs (Rol_STUDENT,Sco_SCOPE_CRS);
-      NumTotalUsrs = Gbl.Usrs.LstUsrs[Rol_TEACHER].NumUsrs +
-                     Gbl.Usrs.LstUsrs[Rol_STUDENT].NumUsrs;
-     }
+   else
+      Gbl.Msg.ShowOnlyOneRecipient = false;
 
    /***** Start frame *****/
    Lay_StartRoundFrame (NULL,
@@ -230,17 +206,40 @@ static void Msg_PutFormMsgUsrs (char *Content)
    if (Gbl.Msg.ShowOnlyOneRecipient)
       /***** Form to show several potential recipients *****/
       Msg_PutLinkToShowMorePotentialRecipients ();
-   else if (NumTotalUsrs)
+   else
      {
-      /***** Form to select type of list used for select several users *****/
-      Usr_ShowFormsToSelectUsrListType (ActReqMsgUsr);
+      /***** Get list of users belonging to the current course *****/
+      if (GetListUsrs)
+	{
+	 /***** Get and update type of list,
+		number of columns in class photo
+		and preference about view photos *****/
+	 Usr_GetAndUpdatePrefsAboutUsrList ();
 
-      /***** Check if it's a big list *****/
-      ShowUsers = Usr_GetIfShowBigList (NumTotalUsrs,"CopyMessageToHiddenFields()");
+	 /***** Form to select groups *****/
+	 Grp_ShowFormToSelectSeveralGroups (ActReqMsgUsr);
 
-      if (ShowUsers)
-	 /***** Get lists of selected users *****/
-	 Usr_GetListsSelectedUsrsCods ();
+	 /***** Get and order lists of users from this course *****/
+	 Usr_GetListUsrs (Rol_TEACHER,Sco_SCOPE_CRS);
+	 Usr_GetListUsrs (Rol_STUDENT,Sco_SCOPE_CRS);
+	 NumTotalUsrs = Gbl.Usrs.LstUsrs[Rol_TEACHER].NumUsrs +
+			Gbl.Usrs.LstUsrs[Rol_STUDENT].NumUsrs;
+	 if (NumTotalUsrs)
+	   {
+	    /***** Form to select type of list used for select several users *****/
+	    Usr_ShowFormsToSelectUsrListType (ActReqMsgUsr);
+
+	    /***** Check if it's a big list *****/
+	    ShowUsers = Usr_GetIfShowBigList (NumTotalUsrs,"CopyMessageToHiddenFields()");
+
+	    if (ShowUsers)
+	       /***** Get lists of selected users *****/
+	       Usr_GetListsSelectedUsrsCods ();
+	   }
+
+	 /***** Get list of users' IDs or nicknames written explicitely *****/
+	 Usr_GetListMsgRecipientsWrittenExplicitelyBySender (false);
+      	}
      }
 
    /***** Start form to select recipients and write the message *****/
diff --git a/swad_user.c b/swad_user.c
index 7fdbfc4e6..f971ed9a9 100644
--- a/swad_user.c
+++ b/swad_user.c
@@ -4556,7 +4556,8 @@ bool Usr_GetListMsgRecipientsWrittenExplicitelyBySender (bool WriteErrorMsgs)
    extern const char *Txt_There_are_more_than_one_user_with_the_ID_X_Please_type_a_nick_or_email;
    extern const char *Txt_There_is_no_user_with_ID_nick_or_e_mail_X;
    extern const char *Txt_The_ID_nickname_or_email_X_is_not_valid;
-   unsigned Length;
+   size_t LengthSelectedUsrsCods;
+   size_t LengthUsrCod;
    const char *Ptr;
    char UsrIDNickOrEmail[1024+1];
    struct UsrData UsrDat;
@@ -4565,6 +4566,7 @@ bool Usr_GetListMsgRecipientsWrittenExplicitelyBySender (bool WriteErrorMsgs)
 
    /***** Allocate memory for the lists of users's IDs *****/
    Usr_AllocateListSelectedUsrCodAll ();
+   LengthSelectedUsrsCods = strlen (Gbl.Usrs.Select.All);
 
    /***** Allocate memory for the lists of recipients written explicetely *****/
    Usr_AllocateListOtherRecipients ();
@@ -4690,18 +4692,22 @@ bool Usr_GetListMsgRecipientsWrittenExplicitelyBySender (bool WriteErrorMsgs)
                if (!Usr_FindUsrCodInListOfSelectedUsrs (UsrDat.EncryptedUsrCod))        // If not in list ==> add it
                  {
                   /* Add encrypted user's code to list of users */
-                  if ((Length = strlen (Gbl.Usrs.Select.All)) == 0)        // First user in list
+                  if (LengthSelectedUsrsCods == 0)        // First user in list
                     {
                      if (strlen (UsrDat.EncryptedUsrCod) < Usr_MAX_BYTES_LIST_ENCRYPTED_USR_CODS)
                         strcpy (Gbl.Usrs.Select.All,UsrDat.EncryptedUsrCod);        // Add first user
                     }
                   else        // Not first user in list
-                     if (Length < Usr_MAX_BYTES_LIST_ENCRYPTED_USR_CODS + 1 + strlen (UsrDat.EncryptedUsrCod))
+                    {
+                     LengthUsrCod = strlen (UsrDat.EncryptedUsrCod);
+                     if (LengthSelectedUsrsCods + (1 + LengthUsrCod) < Usr_MAX_BYTES_LIST_ENCRYPTED_USR_CODS)
                        {
                         // Add another user
-                        Gbl.Usrs.Select.All[Length] = Par_SEPARATOR_PARAM_MULTIPLE;
+                        Gbl.Usrs.Select.All[LengthSelectedUsrsCods] = Par_SEPARATOR_PARAM_MULTIPLE;
                         strcat (Gbl.Usrs.Select.All,UsrDat.EncryptedUsrCod);
+                        LengthSelectedUsrsCods += 1 + LengthUsrCod;
                        }
+                    }
                  }
               }