Fixed font won't update when scroll to item

[draveness]

Reproduce step:

1. set highlighted font and highlighted color, in viewDidLoad

   _pickerView.font = [UIFont systemFontOfSize:26];
   _pickerView.highlightedFont = [UIFont systemFontOfSize:44];
   _pickerView.textColor = UIColorFromRGB(0x91EAFF);
   _pickerView.highlightedTextColor = UIColorFromRGB(0xffffff);
   

2. call [_pickerView selectItem:2 animated:YES]; in viewDidAppear:

The first text color and font won't change