A minor UI improvement to Firefox has been made to Firefox and it’s currently only available on nightly builds of Firefox: the Stop and Reload buttons have been merged into a single button. This change should make it into Firefox 3.6.

While a page is loading, the button acts as a Stop button:

When it’s done loading, it becomes a Reload button.

I’m always up for 1 less unnecessary button. I think this feature is copied from Safari (I might be wrong).