If an element is overflow:hidden
and we use the browser's text search functionality to find text that is within that element, but it's not visible, Chrome will move that element so that the search result will be visible to the user.
You can see this happening here: http://codepen.io/anon/pen/qdayVz Open the link in Chrome and search for text that is not in the visible, "CCC" for example, and you will see that Chrome will move the element to show the found text.
Here is a real world example: http://www.jssor.com/demos/full-width-slider.html -- Search for text that is not in the visible slide.
This does not happen in Firefox.