And while you're at it, take a peek at how it is implemented in other tools as well:
SketchUp -> rest get's dim & transparant, but still visible as a reference. You have control over this visibility in the preferences.
VectorWorks -> editing a group of elements or a symbol (aka "block" in AutoCAD terms) always happens in the same way. Here the rest of the drawing gets hidden, though.
Strata3D -> an "instance" of a shape can be opened in a new window and edited at will. The rest of the scene updates if you close that window again.
---> All these systems are very fast and don't require to open a new element, modify and save changes to be able to continue.
The AutoCAD way of in-place block & reference editing is not that fast and clear to see what you are doing, but it was a major improvement over the past (where you had to either create a new block & redefine or open the other drawing, save changes and, in case of a block, insert the file into the drawing again).
I hardly use modules, but I don't do large projects, so it is possible that I underestimate their importance.
--- stefan boeykens --- bim-expert-architect-engineer-musician ---
ARCHICAD-user since 1998