title: Highlighting box for provisional data on Viz
body: <p>I would like to create a box(shaded with a different color to the background) to show the fact that the last 3 days are provisional data. I want to do this on a line chart that has date on the x-axis and a value on the y-axis. If there is a filter on the dates displayed the box should only show up on the last three days relative to the current date(which is the last date in the date field).</p>