GNOME Shell does not show "User Actions" menu if only one session exists
When using GNOME Shell 3.28.0, if there's only one session available, the "User Action" menu, along with the "Log Out", "User Settings" menu items are hidden. In the case of our distro (AOSC OS), we have removed the Wayland session by default in interest of usability, therefore, in a default GNOME installation, the only session would be /usr/share/xsessions/gnome.desktop.
In this case, if one were to install, say, XFCE, along with its /usr/share/xsessions/xfce.desktop, and restart the GNOME Shell via Alt-F2 and "r", the "User Actions" menu reappears. Removing XFCE will revert to the hidden menu.
Not sure what happened here, but hopefully this is not intended. It is a bit naive, IMHO, to assume that there's no need to log out or change user settings conveniently if only one session exists.