From MozillaZine Knowledge Base
Mozilla Firefox’s Places system keeps metadata about browsing sessions in history. This allows the history sidebar to group pages by browsing session as well as by last visit, which can be a useful distinction when trying to find a previously-visited page.
For UI parity with Firefox 2.0, this preference disabled browser session grouping for page history in the history sidebar.
Possible values and their effects
When “View → By Last Visited” is selected in the history sidebar, group the visited pages by browsing session and delineate them with horizontal rules.
Do not group pages in the history sidebar; display them as they appear in Firefox 2.0. (Default)
First checked in
2006-12-08 by Seth Spitzer (patch by Dan Mills)
Has an effect in
- Mozilla Firefox (trunk builds between 2006-12-08 and 2007-01-11)
- Bug 359349 - [rfe] when "view | by last visited" in history sidebar, show "sessions"
- Bug 366589 - Avoid places URI parsing in the history sidebar as much as possible