Modal/Modal.php
static protected function getButtonOptionsResolver()
    {
        if (null === static::$buttonOptionsResolver) {
            static::$buttonOptionsResolver = new OptionsResolver();
            static::$buttonOptionsResolver
                ->setDefaults([
                    'id'       => null,
                    'icon'     => null,
                    'label'    => null,
                    'autospin' => null,
                    'cssClass' => 'btn-default',
                    'hotkey'   => null,
                ])
                ->setAllowedTypes('id',       'string')
                ->setAllowedTypes('icon',     ['null', 'string'])
                ->setAllowedTypes('label',    'string')
                ->setAllowedTypes('autospin', ['null', 'bool'])
                ->setAllowedTypes('cssClass', 'string')
                ->setAllowedTypes('hotkey',   ['null', 'int'])
            ;
        }
        return static::$buttonOptionsResolver;
    }
static protected function getButtonOptionsResolver()
    {
        if (null === static::$buttonOptionsResolver) {
            static::$buttonOptionsResolver = new OptionsResolver();
            static::$buttonOptionsResolver
                ->setDefaults([
                    'id'       => null,
                    'icon'     => null,
                    'label'    => null,
                    'autospin' => null,
                    'cssClass' => 'btn-default',
                    'hotkey'   => null,
                ])
                ->setAllowedTypes('id',       'string')
                ->setAllowedTypes('icon',     ['null', 'string'])
                ->setAllowedTypes('label',    'string')
                ->setAllowedTypes('autospin', ['null', 'bool'])
                ->setAllowedTypes('cssClass', 'string')
                ->setAllowedTypes('hotkey',   ['null', 'int'])
            ;
        }
        return static::$buttonOptionsResolver;
    }
Returns the button options resolver.

@return OptionsResolver