There's no information provided to FormView#on_loaded which should change the sidebar and reloading it apparently breaks stuff... severely. So just don't touch it if it's already setup (assigned to instance variable), everything works right (as the readonly mode fundamentally only changes the way the form is displayed, it should not alter its internal behaviors) lp bug: https://launchpad.net/bugs/891117 fixed bzr revid: xmo@openerp.com-20111122102609-faldd3xkc0xhzvu2