Scrollbars became flat. May be it looks not bad on Windows 10, but on Windows 7 much better looks standard non-flat scrollbars. So add please option to select its drawing style.
Main menu and context menu background became dark gray. Well, it also would be good to be able to select.
The scrollbar and menu colors are linked to the "GUI background color" of Atlantis. It can be changed through the "Tools | Quick Personalization..." menu command of Atlantis.
I am sorry, but the design of the scrollbars in the document window of Atlantis is not customizable.
The scrollbars consist of multiple components. Each component has its color linked to the current color theme of Atlantis. So the scrollbars are not just gray.