These pseudo elements and pseudo class selectors work together. We plan to extend it to work with any content and to propose it as a new standard pseudo-class.) All together now Some layouts set html and body to 100 height, and use a wrapper div with overflow: auto (or scroll), thereby moving the scrolling to the wrapper element. (In recent nightlies, this pseudo-class now applies to ::selection as well. If anyone here is having a problem with disabling scrollbars on the iframe, it could be because the iframe's content has scrollbars on elements below the html element. But to do so, you should have access to iframe content. To get rid of scrollbars apply overflow:hidden and height/width:100 to html, body of iframe (or to element that has overflow:auto in iframe content). :window-inactive – Applies to all scrollbar pieces and indicates whether or not the window containing the scrollbar is currently active. Looks like you see scrollbars of iframe content, not iframe itself.
:corner-present – Applies to all scrollbar pieces and indicates whether or not a scrollbar corner is present. The HTML