After a dual-boot Windows 10/Ubuntu 18.04 installation, it looked like the PC was booting straight to Ubuntu, without showing the GRUB menu, after a short pause. I had already run Boot Repair under Ubuntu and checked bcdedit under Windows.
It turned out, during boot I had to hit the Esc key when the screen turned Ubuntu-purple, in order to display the GRUB menu and be allowed to choose the OS to boot. Not pressing Esc, after a time-out, the PC would boot to the default (Ubuntu).
I don't want to have to hit Esc every time during boot: how can I have the boot process show the GRUB menu right away, with no need for me to hit Esc?