SFSafariViewController无法以纵向模式工作

Question

我正在模拟器中试用iPad Pro上的新SFSafariViewController。它适用于风景而非肖像。这是我的代码：

NSURL *URL = [NSURL URLWithString:[NSString stringWithFormat:@"https://forums.greenrobot.com"]];
if ([SFSafariViewController class] != nil) {
    //SFSafariViewController *sfvc = [[SFSafariViewController alloc] initWithURL:URL];
    SFSafariViewController *sfvc = [[SFSafariViewController alloc]initWithURL:URL entersReaderIfAvailable:YES];

    [self presentViewController:sfvc animated:YES completion:nil];
} else {
    [[UIApplication sharedApplication] openURL:URL];
}