UIButton underline

Looks like UIButtons are highlighted by this underlining whilst UIBarButtonItem get a dark background. Did not find a way to change underlining. But did you try to disable the accessibility checkbox for those buttons you don't want to underline ?

Not entirely sure if you understand what am I trying to do

Trying to remove underline in button for ex. this image

I found this article: http://stackoverflow.com/questions/23246543/remove-underline-on-uibutton-in-ios-7

But im not sure how to make it in swift. I'm newbie to swift. This article is not working while in Settings > General > Accessibility > Button Shapes is enabled

Thanks