From MozillaZine Knowledge Base
Some web sites choose to open certain links in new windows. This preference lets you control where to open these links, that would normally open new windows. You can use browser.link.open_newwindow.restriction to fine tune which links will be affected by this preference.
Possible values and their effects
Open links, that would normally open in a new window, in the current tab/window.
Open links, that would normally open in a new window, in a new window (Default in Firefox 1.5 and older).
Open links, that would normally open in a new window, in a new tab in the current window (Default in Firefox 2.0 and newer).
First checked in
Has an effect in
- Mozilla Firefox (all versions since 1.0)
- SeaMonkey (all versions)
- Bug 172962 - Options for where to open URLs from other applications (reuse tab, new tab, new window)