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