Pretty grub layout lile in VBox demo

Hi all. When I started to learn about nixos with help of virtual-box demo it has a pretty grub menu with the latest nixos generation in main menu and others hidden in special option. But in hardware installation grub shows all generation in main menu and I can not find instruction or option, how to move old generations to submenu. Is there such topic in documentation, or can someone share knowlage on subject?

Are you sure is the grub menu? Because I recently switched to a new hardware and I kept the default nixos config that uses systemd- something to boot, and it shows all the generations on the main menu directly… what’s your boot. config?

Yes, shure it is, thank you. I will try to switch to grub later.