--- /dev/null
+This extension require a callback that is not yet present (at RT 4.0.0 time) in share/html/Ticket/Display.html.
+
+To add it, got to /path/to/your/rt, then run the following command:
+
+For RT 4.0.0:
+patch -p1 < /path/to/this/extension/rt-4.0.0-AfterMessageBox.patch
+
+For RT 3.8.10:
+patch -p1 < /path/to/this/extension/rt-3.8.10-AfterMessageBox.patch
+
--- /dev/null
+diff --git a/share/html/Ticket/Update.html b/share/html/Ticket/Update.html
+index 50c6f93..94e9a94 100755
+--- a/share/html/Ticket/Update.html
++++ b/share/html/Ticket/Update.html
+@@ -144,6 +144,7 @@
+ % $IncludeSignature = 0 if $Action ne 'Respond' && !RT->Config->Get('MessageBoxIncludeSignatureOnComment');
+ <& /Elements/MessageBox, Name=>"UpdateContent", IncludeSignature => $IncludeSignature, %ARGS &>
+ % }
++% $m->callback( %ARGS, CallbackName => 'AfterMessageBox' );
+ </td></tr>
+ </table>
+
--- /dev/null
+diff --git a/share/html/Ticket/Update.html b/share/html/Ticket/Update.html
+index de3461e..0c41491 100755
+--- a/share/html/Ticket/Update.html
++++ b/share/html/Ticket/Update.html
+@@ -178,6 +178,7 @@
+ % $IncludeSignature = 0 if $Action ne 'Respond' && !RT->Config->Get('MessageBoxIncludeSignatureOnComment');
+ <& /Elements/MessageBox, Name=>"UpdateContent", IncludeSignature => $IncludeSignature, %ARGS &>
+ % }
++% $m->callback( %ARGS, CallbackName => 'AfterMessageBox' );
+ </td></tr>
+
+ <& /Ticket/Elements/AddAttachments, %ARGS, TicketObj => $TicketObj &>