I have 3 hdd
1.Main with grub menu Qubes os
2. Manjaro Linux for mobile app development.
3. Windows 10 for gaming only 
But When I boot, Qubes grub menu pops up but there is only Qubes os.
If I edit GRUB_DISABLE_OS_PROBER="false" in /etc/default/grub file
and then
sudo grub2-mkconfig -o /boot/grub2/grub.cfg
Does this make other os shows up in grub menu?