I would like to have the option on Revit to show dimension totals on Properties palette on multiple selection, when selecting similar elements. At least for dimensions like Length, Area, Perimeter and Volume (better if all numeric parameter).
That would save times when someone what to know the total value of various elements without creating a schedule an configure it only for one time for various categories indivually or having to calculate it manually.

Of course, there's scenarios when viewing the common value is more useful, so there will be a place to configure what to shows, as we do informating for schedule.
That could be implemented with an Option Button on Properties palette (for more flexibility) or in the Multiple Values Indication window (Manage tab).
