Trouble with usability is that its success will depend on user habits. For example, Louis seems to think of Xpress usability as a nightmare.I think it is much better than InDesign. I think InDesign is not usable because everything is in menu, everything is in windows, everything is everywhere. Of course, anybody can find his solution with that. But when you want to work fast, it is becoming harder.
We have to keep in mind that those concepts don't follow precise rules even if some ideas can be followed. cedric.
