Nested Frames (one frameset within another frameset)

The current function to use framesets is nice, but still a bit limited as framesets cannot be nested into each other. Sometimes you use a frameset for the overall application design - esp. to provide global menu bars and navigation structures. On the other hand you would also need a frameset for specific report layouts (e.g. to avoid stretching of charts next to dynaranges). But currently you cannot combine them for more complex, professional layout: If you use framesets for menubars/headers/footers with a content frame, then you don't have the option anymore to structure also you content into frames. Therefore it would be great to have the option to tag a frameset itself as "frame", to use it within another frameset. ..see attached picture