From MozillaZine Knowledge Base
When more tabs are present on the tab strip than can be displayed at once, the tab strip becomes scrollable to handle the overflow. Switching to another tab that is not currently in view will cause the tab strip to scroll so that the tab is visible. This preference determines whether to scroll the new tab into view smoothly, or to have it snap into view.
Possible values and their effects
Scroll the tab strip smoothly to a newly-selected tab. (Default)
Move to the new tab immediately.
First checked in
2007-08-15 by Ryan Flint (patch by Michael Ventnor
Has an effect in