Or just tell them to switch tabs. Another sign is that if a dialog was actually showing, the browser window wouldn't look focussed. e.g. on Windows the browser

Or just tell them to switch tabs. Another sign is that if a dialog was actually showing, the browser window wouldn't look focussed. e.g. on Windows the browser looks like this: http://i.imgur.com/nbn9K.png http://i.imgur.com/nbn9K.png instead of this: http://i.imgur.com/7F3FD.png http://i.imgur.com/7F3FD.png