From MozillaZine Knowledge Base
This preference controls what should be loaded in newly created window. It doesn't affect what is loaded at startup or in new tabs.
Possible values and their effects
Load the default home page in the new window.
Load nothing in the new window.
Load the user's homepage in the new window. (Default)
Load the last visited page in the new window.
Mozilla Suite and SeaMonkey
When “New Window” is selected in “Edit → Preferences → Navigator → Display on”, the radio buttons “Blank page,” “Home page,” and “Last page visited” toggle between 0, 1, and 2, respectively.
First checked in
Has an effect in