2.x has gone through major refactoring and there are some observable differences in UI and feature from 1.x version.
Select time range from [Today, Yesterday, Last 7 days, This month, This year, All] (default is Today). Search terms take effect when the time range is changed.
The thread roots are ordered by latest visit first.
context menu is now the same as that of a normal link in any web page. Currently there's no way to expand all the threads. (Lost due to upgrade)
If there are new visits while the view is open, the view needs to be manually refreshed by hitting enter in search bar (including when it's empty).
No option in Preference to override hotkey of Firefox's built-in history sidebar. (Lost due to upgrade)
(Lost due to upgrade) Extensions based on this addon
You can delete browsing history by threads using this addon:
Clear History by Threads