Ok... I think i've got to a final conclusion about the right interface.
I fixed the drag+right click interface, and it looks like the best one so far (the drag,release,left-click is a bit uncertain, sometimes, it can not do anything).
I also added a gui, that appears 1second and a half (in the next versions, it'll be costumizable), and has information on where the groups are.
The middle-button drag + right-click interface is also enhanced, it looks really good now. (try it, i'm sure you'll love it
I also have been testing with overlapping groups, and it works great, and has a fantastic effect.
I've had another idea (which i think is similar to your original idea):
Instead of having only areas, we could make each of the areas have a specific "trigger area", which might (or might not, depending on how the user wants it) be different from the area itself. The big advantage of it would be that the program might actually work only by dragging, and if the mouse was in a trigger zone, the window would be resized to fit the corresponding area.
(now that i think about it... this was exactly your first idea wasn't it? i'm sorry, i think i only understood it now)GridMove Beta1