One of the most requested features I have seen to date for Safari, especially coming from recent switchers from Windows, has been for Safari to run in single window mode – i.e., force links that would normally open in a new window to open in a new tab in the active window instead. Well, Apple has finally answered these prayers with the release of version 3.1. First of all, launch Safari and go into its preferences, then the General pane. At the bottom, where it says “Open links from applications,” select “in a new tab in the current window.” This way, clicking a link in, say, Mail, will open a new tab instead of a new window in Safari. Now launch (/Applications/Utilities/Terminal). When it comes up, copy and paste the following line, then hit return:

defaults write TargetedClicksCreateTabs -bool true

Now quit Terminal and restart Safari. Safari should now be running in true single window mode. Clicking links that typically open a new window will now open new tabs instead. To reverse this change and disable single window mode, change “true” in the above Terminal command to “false.”