After Joel Spolsky posted that disabling unusable menu items is bad design, the rebuttals came pouring in, from Gruber, from Jalkut, from Mathis, and others.

The argument is that if you are unable to use a menu item, then you should still be able to click it, and then a dialog would appear telling you why it cannot be used. The other behavior is to simply disable, “grey out” the item so it cannot be clicked on at all. As a long time user who has been thinking very much about interface and interaction, I think the second is a far better option because it does not present a false implication that the item is usable. I do not like to click something and then be told, almost punitively, that I cannot get what I want. If the system could tell me that in a quicker, quieter, less misleading way, I’m for it. Greying out menu items is a great way to do that.

One of the things I loathe about Windows is the way it condescendingly explains things — everything — to me. Most of this I already know and I just feel talked down to while using it. Good, user friendly UI isn’t about assuming the user is stupid. It’s about respecting the user and realizing there are certain things the user doesn’t want or need to care about. The more the UI can get out of the way, the more information that can be implicitly passed onto the user without spelling it out in paragraph form, the better.