Elastic Windows is a windowing approach where windows are organized in a hierarchical fashion on a space filling tiled layout, developed by Eser Kandogan and Ben Shneiderman between 1996 and 1998. According to its evaluation, "results suggest promising possibilities for multiple window operations and hierarchical nesting, which can be applied to the next generation of tiled as well as overlapped window managers". However, I couldn't find any windowing manager or application that implements hierarchical tiled windows. Can you name such a system that is operational as of now? (Note that most tiling window managers only implement tiling but not hierarchical nesting, which is a key to organization since it preserves relationships between the pieces of data displayed in the windows.)
Most of the comments seem to suggest that a modern version of the elastic windows implementation doesn't exist or is not in popular use, and I would like to offer a theory on why this might be the case.
As you can see from the screenshot in the question, this type of interface arrangement may have been more suitable during a period when the volume and complexity of content and applications that we have to manage were a lot more modest compared to these days. The fact that we haven't developed more sophisticated methods to manage the multitude of information suggests that this may not be the optimal strategy or solution. In fact, this is one of the reasons why search is starting to overtake navigation for complex software applications except when there is a need to fixed reference points for the user.
Conversely, if we were somehow able to reverse the trend (or if the cycle comes back) and start designing less complex applications and interfaces (visually, so an example would be conversational interfaces that abstract away the mechanical interactions) then I could see this style of layout becoming more popular. It doesn't seem like a viable solution to the amount of information and applications that are being developed at the rate they are being developed.
Furthermore, using the current UI design conventions, if each window contained a large number of content, it would be quite impossible to retain the overview that you would be able to take advantage of which such as layout system. The fact that a user will have to scroll (both horizontally and vertically) to navigate through and find content will almost certainly be a sticking point that needs to be overcome.
I would like to know if there are other thoughts and ideas on this rather interesting question.