Thunderbird: how to get back the folder view switching arrows?

Question

The folder pane in Thunderbird used to have a left and right arrow that allowed switching between the folders displayed. However, since a week or so, the arrows are gone (update? miss-clicked something?)

As I use them several times a day: how can I get the arrows back? I have Thunderbird 8.0.

Note: I know, switching is also accessible via the menu bar > View > Folders, but this is too much clicks for me.

Answer 1

Apparently it's a 'feature' of Thunderbird 8 (from the 8.0 release notes).

The latest version of Thunderbird has the following changes:

• Folder switching pane widget has been removed, can be added back with the Folder Pane View Switcher Add-on

Great, well done, Mozilla :-| From the add-on reviews seems I am not alone in thinking that Mozilla is taking some strange (and wrong) decisions here.