MFP 7.1下拉菜单在ios11中不能正常使用

I'm using MFP7.1 and xcode 9 to develop my application on ipad platform. I'm facing an error when clicks on drop down menu button. When I select a value, the drop down list will close and re-open. Then, when I tap on the second drop down menu button, the first drop down list will re-open but the selection on the first drop down list will missing. The second drop down list will not appear. The drop down menu button is function normally when I develop using xcode 8. This issue only happen when the application is develop using xcode 9 and running in iOS 11.I'm using MFP7.1 and xcode 9 to develop my appl