Chrome Version: 59.0.3071.115

What steps will reproduce the problem?
(1) Open http://sentence.yourdictionary.com/
(2) Scroll down till the menu bar disappears or run the following from console "window.scrollTo(window.scrollX, 230)"

What happens?

The menu bar disappears and appears repeatedly due to the following logic:
            if (($(window).scrollTop() >= 230))
            {
                $('#site-menu-div').css({"display": "none"}); 
                            $('#top_spacer').css({"height": "185px"}); 
                $('.floating-header').css({"top": "100px"}); 
            }
            else 
            {
                $('#site-menu-div').css({"display": "block"}); 
                            $('#top_spacer').css({"height": "230px"}); 
                $('.floating-header').css({"top": "145px"}); 
            }

Note:
1. This website may be very popular because whenever users search "use something in a sentence" that's the first result they would see.
2. There was another similar issue about this. List it here for ref.  crbug.com/734461 


Steve, could you please take a look? Thanks!