Once you land in the admin area there is a menu similar to the old site, but laid out differently. This new menu opens and closed automatically, in the old site each area stayed open until you closed it yourself manually, allowing yourself to flow through the site at ease.
Usually when working in an area you are in and out of the same area completing tasks, this auto closing is a real pain and means extra clicks to manoeuvre the menu, good cause for RSI and not user friendly.
In addition when a menu stays open the brain is actually learning where things are more quickly to navigate the site. At the moment it feels a little crazy running round a huge hallway opening doors and thinking where is that item I need because its not visible with all these doors shut !!
Access please let us decide if we want to leave a menu open and remove the auto shut causing us extra work and blindness to what's behind the door.