One of the greatest new features of FileMaker over the last 7 years was the addition of subsummaries in browse mode (in FileMaker 10). Made the "list view" a million times more functional for viewing, creating, and editing data! It opened up entire new worlds of possibilities to all of us.
Would be great to somehow have subsummaries in portals as well. Yes, this can sort of be kludged together with either a virtual list technique or using the GetNthRecord function on each portal row (along with the "hide object" functionality). And, of course, we can always send the users to a list layout to see their records subsummarized. But would still be great to somehow have native built-in subsummaries in portals when portal line items are sorted.
No idea how this could be built natively into FileMaker, but would be absolutely amazing!!