I have also add a fiddle of the project here:
When if first loads you will notice the horizontal scroll bar is not active to be used. If you resize the browser the window resize event will resize the pivotgrid the way it should. If you then filter on the service areas the scroll bar disappears again until a window resize event. So it seems to be a problem after a data bind. This leads me to two things I want to try and make happen:
1) either find a place I can resize the pivotgrid after data bind and the subsequent painting of the widget with data on the page...or
2) load the data synchronously(not ideal) load the widget and data and refresh/resize the control
However, I am not sure either one of these will be easily accomplished if at all.