Under iOS 11 it seems that UIBarButtonItems of type UIBarButtonSystemItemFlexibleSpace have no effect anymore in a navigation bar. I've used them to get more space between certain groups of icons on devices with larger screens. This works fine under iOS 10 and older, but under iOS 11 all icons are "squeezed" together on one side. So adding UIBarButtonItems of type UIBarButtonSystemItemFlexibleSpace looks like there were no such buttons added at all.
What exactly must be done under iOS 11 to distribute the available space between the icon groups?
