"A long time ago, it became fashionable, even recommended, to disable
menu items when they could not be used.
Don't do this. Users see the disabled menu item that they want to
click on, and are left entirely without a clue of what they are
supposed to do to get the menu item to work.
Instead, leave the menu item enabled. If there's some reason you can't
complete the action, the menu item can display a message telling the
I agree about the hiding, but I don't think I necessarily agree about
the disabling. What is missing from his critique is how "the menu item
can display a message telling the user why." Does he mean pop-ups?
I'd rather set the users' expectations correctly than to have them
click on a menu item and have a pop up appear telling them why they
can't do that. A really long tooltip: "If you want to Paste an object,
first you need to unlock this layer." is definitely better, but could
have tons of conditionals.