No option to drop down the list in any field and scroll across the list by using up/down arrow of keyboard. The drop down and selection of any item should be done by keyboard without using mouse.
This is a function of your operating system, not Manager. It can also depend on which edition (desktop, server, or cloud) you are using. Different operating systems and browsers behave differently in this regard. On a Mac, for example, the program behaves exactly as you describe.
Can you please suggest which operating system and which edition of manager supports this?
I only know it behaves that way on the desktop edition for macOS. I don’t know about other editions or operating systems.