Safari Preferences Click to see a larger image

Even if you try to keep organized with one single window, many websites will open a new window automatically when you click a link. Safari 5 tries to reduce that behavior.

In the Tabs tab of Safari Preferences, the first option is "Open pages in tabs instead of windows." Safari 5 defaults to "Automatically" but if you don't like this behavior you can turn if off.

With this option turned on, Safari will try to override a websites attempt to open a new window and will instead open the page in a new tab. This behavior works most of the time but still opens some pages in their own window. This has mostly been the case when you click a "help" link on a page and a small window opens over the top of your current page with help information. That behavior makes sense because you will probably read what is in the help window, close it, and go about your work. You can force Safari 5 to open every link in a new tab by choosing "Always."