Left pane in mail view is not compact as before

[rCj7t993swwMeDsm]

From the demonstration screenshot (https://github.com/grommunio/grommunio-web/blob/master/doc/grommunio-web-ui.png), the left pane in mail view is that compact:

but the left pane is loosen in the recent version:

This made mail box with long folder list inconvenient to navigate.
It is more helpful to make it compact for the users with long folder list.