Might be more fruitful to think of a graph or tree "ecosystem" rather than just an editor. For an ecosystem one can think of the following aspects: - a represe

Might be more fruitful to think of a graph or tree "ecosystem" rather than just an editor. For an ecosystem one can think of the following aspects: - a representation that can be shared by various tools, possibly in parallel. Allow attaching arbitrary attributes - ability to map between equivalent but different representations (adjacency matrix, node/link/port etc.) - plugins that operate on a specific rep. and map to some visual representation - a language for programmatic construction (or may be a library) - efficient storage representation (one or more) - communication protocol for sharing/moving subgraphs - key/mouse bindings when viewed graphically - macros/functions to encapsulate useful patterns - graph manipulation & mapping tools (e.g. mapping a circuit schematic to a PCB, compiling, etc.) [Sorry for the frequent editing - I was trying to get the list right. Still not quite right.]