How do to get Windows back in the grub menu?

I have a Dell laptop with Windows 10 and I installed Tumbleweed next to it and got a grub menu in which I could select which one to start. After installation of Leap 15.4 beta, next to Tumbleweed and Windows 10 I only got Leap 15.4 and Tumbleweed in the grub menu. I tried in both openSUSE systems to run "yast bootloader", but no Windows. I found a recipe to get other bootable systems in grub by running the command os-prober and update-grub, however os-prober does not show any sign of windows. So update-grub will not add Windows in the menu. How do I get Windows 10 back in grub? Also the Bios does not show an entry to boot Windows. -- fr.gr. member openSUSE Freek de Kruijf