If you’re a web developer of any kind, you should get the Firebug extension for Firefox. It’s a neat little tool that allows you to inspect and manipulate the DOM in place. It’s a clever little tool. This is what the DOM Inspector should’ve been.

For some reason, horizontal scrolling in Firefox causes the app to go back or forward in the browser history (i.e. the Back and Forward buttons in your browser). That’s just a weird default. It’s even more annoying with the Mighty Mouse because it’s so easy to inadvertently scroll to the side as you’re scrolling down quickly. It’s the problem with this kind of design where you have freedom to move diagonally.

The good news is that you can fix it in Firefox so that it behaves like a normal application. If you want Firefox to simply scroll the window horizontally when you use the horizontal scroll bar, follow these steps:

1. In the location bar (where you type in the URL/web site address), type about:config . This will present you with a list of hidden preferences that control Firefox
2. Find the following entries in the list:

   mousewheel.horizscroll.withnokey.action
   mousewheel.horizscroll.withnokey.numlines

3. Change mousewheel.horizscroll.withnokey.action to 0 in the Value column
4. Change mousewheel.horizscroll.withnokey.numlines to 1

That should do it. Try scrolling horizontally and you’ll be all set.