**Problem:**

There appear to be many tools for visualizing graph structures, but none of the ones I've seen so far seem to have the feature of "nesting". The WireIt library (apparently inspired by Yahoo Pipes) looks very promising, but it seems to lack this concept of nesting.

To explain what I am thinking of, consider a Company Org Chart where each "box" in the Org Chart has a button with three dots [...] 

When you click on the button, the chart "drills down" into the sub-organizations within the node you just clicked on, you can use the backspace key (or some other convention) to jump back up to the originating node.

**Question:**

Does anyone know of a GUI toolkit (prefer web-compatible) that includes this concept of nesting? The WireIt library looks promising, but if there are any others out there you are aware of, feel free to include that also.

TIA for any info.