On the list of the widget areas on the right:
- have some kind of indicator on the title of each widget area to show if that widgetized area has any widgets assigned to it.
- Or better yet, show the number of widgets in that area. That way we don't have to expand each accordion heading to see if it contains any widgets.
In the available widgets area:
- a checkmark next to the title of each widget to indicate whether that widget is in use - i.e., assigned to one of the widget areas on the right