Firefox preferences allow you to control how tabs respond to certain types of events. Some of the preferences are easily set in the Preferences window, while others require you to use the special about:config page in the browser.

• Links from other applications

When a link is sent from another application, such as when you click on a URL in an email, what should the browser do? There are three options: open the page in a new window, open the page in a new tab in the front window, or replace the current page in the front window.

The options for this behavior are shown at the top of the Tabbed Browsing panel in the Preferences window. If you ever feel the need to set this preference via about:config, look for browser.link.open_external. Setting this preference to 1 opens the link in the current tab and window, 2 opens it in a new window, and 3 opens it in a new tab in the front window.

• Loading tabs in the foreground or background

There are three preferences that control whether new tabs load in front of the current tab or behind it. These preferences correspond to the three types of events that can open a new tab. Two can be set in the Preferences window (checked or true means “load in foreground”; unchecked or false means “load in background”), while the third requires the about:config page, described earlier in this hack:

Control (Command)-clicking a link in the browser to open a new tab

Set this in the Preferences window with the checkbox labeled “Select new tabs opened from links” or in about:config by changing browser.tabs.loadInBackground.

Opening a tab from a bookmark or the browser history panel

In the Preferences window, this event is called “Select new tabs opened from bookmarks or history.” In about:config, it’s browser.tabs.opentabfor.bookmarks.

Opening a tab from a link sent by another application

There is no checkbox in the Preferences window for this setting. In about:config, this preference is browser.tabs.loadDivertedInBackground.

• Getting rid of tabs when there’s only one

This preference hides the tab bar at the top of the set of tabs when only one tab exists:

browser.tabs.autoHide  /* set to true to enable hiding */

• Single Window mode

Do you hate it when links on web pages open new windows (because they set a target attribute on the link)? You can force Firefox to open those links in a new tab instead of a new window. This is called Single Window mode. It doesn’t prevent all new windows, but it catches most of them. The radio buttons for setting this preference are in the Preferences window, but only if Firefox knows you want to see them. Go to about:config and set browser.tabs.showSingleWindowModePrefs to TRue.