Asking password popup is very small and can't be resized

On Ubuntu Precise, with version 3.2.1-1, sometimes on some computers, after wake up from sleeping state (suspend to ram), a popup from krb5-auth-dialog is shown for asking kerberos password but the popup has not its full size and we cannot see anything except the top-left corner. We cannot resize the popup so the only way to resolve the bug, it's to kill all "krb5-auth-dialog" processes. While the popup is still open, we can't use keyboard on X server because the focus remains on this "bugged" popup.
After restarting it from unity, it's OK until next "suspend to ram".