- [ ] I have searched the [issues](https://github.com/vueComponent/ant-design-vue/issues) of this repository and believe that this is not a duplicate. ### Version 1.5.5 ### Environment vue 2.6* ### Reproduction link [https://github.com/vueComponent/ant-design-vue](https://github.com/vueComponent/ant-design-vue) ### Steps to reproduce 配置prefixCls,然后查看modal的class前缀 ### What is expected? 希望前缀是全局配置的prefixCls值 ### What is actually happening? modal的class前缀依旧是ant <!-- generated by issue-helper. DO NOT REMOVE -->