500 | Internal Server Error | InvalidArgumentException
Widget schema does not include the following field(s): title
stack trace

    at ()
    in SF_ROOT_DIR/lib/vendor/symfony/lib/widget/sfWidgetFormSchema.class.php line 761 ...
                if ($diff = array_diff($positions, $current))
                {
                  throw new InvalidArgumentException('Widget schema does not include the following field(s): '.implode(', ', $diff));
                }
                if ($diff = array_diff($current, $positions))
    at sfWidgetFormSchema->setPositions(array('title', 'content'))
    in SF_ROOT_DIR/lib/vendor/symfony/lib/form/sfForm.class.php line 1133 ...
                if ($ordered)
                {
                  $this->widgetSchema->setPositions(array_merge($fields, $hidden));
                }
              }
    at sfForm->useFields(array('title', 'content'))
    in SF_ROOT_DIR/lib/form/brickForm.class.php line 23 ...
                $this->widgetSchema->setFormFormatterName('brick');

                $this->useFields(array('title', 'content'));
              }

              public function getModelName()
    at brickForm->configure()
    in SF_ROOT_DIR/lib/vendor/symfony/lib/form/sfForm.class.php line 70 ...
                $this->errorSchema     = new sfValidatorErrorSchema($this->validatorSchema);
                $this->setup();
                $this->configure();
                $this->addCSRFProtection($this->localCSRFSecret);
                $this->resetFormFields();