Comment 4 for bug 823736

Why is forward special? It's inconsistent to hide forward when the user is unable to go forward without doing the same for *at least* back, and hiding any toolbar buttons based on what actions are currently possible seems to conflate visibility and sensitivity. If a user is clicking forward multiple times to try to reach the front of the back-forward list, there's a pretty good chance they'll make a click after forward becomes insensitive, doing something they didn't intend. Keeping the principle of least astonishment in mind, I think it's a good idea to encourage users to have a clear mental model of what the difference between previous/next and back/forward is; if they don't understand the difference they'll be confused when both forward and next buttons are present and when the one present button doesn't do what they expect. Even for power users I doubt there's an expectation for forward to appear and disappear or for the other buttons in the toolbar to move around solely as a result of going back/forward. For less experienced users it may be even more frustrating to not be able to find the forward button when looking for it, whereas having it present and insensitive provides a clear visual cue that has a long history in UI design and should be familiar to users of many systems.

I'm all for making UI improvements, but making unguided special-case changes without a clear usage case doesn't make sense. "Copying Mozilla" is not an effective design strategy.