Firstly for the nomenclature: That is called the notification area. It used to be known as the system tray. When icons are added they land in the overflow section of the notification area automatically. Now, what is it you want to do? Do you as a user want to tell your windows to keep all icons in the notification area visible at all times? Or do you as a developer want to keep your own apps icon visible? For the former there is a solution I'm actually missing in your settings screenshot. There should be a switch to always display all icons in the notification area. Please see my screenshot for that...german, sorry, but you should get the gist of it. If it's the latter, I believe that to be impossible unless you write a Microsoft application... See the Shell Developers Guide for details: https://docs.microsoft.com/en-us/windows/win32/shell/notification-area#add-a-notification-icon