Thanks for your answer.
If the firmware user interface isn't working out for you, boot order can be set
using efibootmgr.
I have now looked at that program.
Interestingly it looks that the bootorder is ok.
$ sudo efibootmgr -v
BootCurrent: 0001
Timeout: 1 seconds
BootOrder: 0000,0001,0008,0007,0006,0004,0005,0002
Boot0000* Windows Boot Manager
HD(1,GPT,9f60665e-5479-407c-9b92-4c63a175ad8f,0x800,0x82000)/File(\EFI\MICROSOFT\BOOT\BOOTMGFW.EFI)WINDOWS.........x...B.C.D.O.B.J.E.C.T.=.{.9.d.e.a.8.6.2.c.-.5.c.d.d.-.4.e.7.0.-.a.c.c.1.-.f.3.2.b.3.4.4.d.4.7.9.5.}....................
Boot0001* opensuse-secureboot
HD(1,GPT,9f60665e-5479-407c-9b92-4c63a175ad8f,0x800,0x82000)/File(\EFI\OPENSUSE\SHIM.EFI)
Boot0002* Windows Boot Manager
VenHw(99e275e7-75a0-4b37-a2e6-c5385e6c00cb)WINDOWS.........x...B.C.D.O.B.J.E.C.T.=.{.9.d.e.a.8.6.2.c.-.5.c.d.d.-.4.e.7.0.-.a.c.c.1.-.f.3.2.b.3.4.4.d.4.7.9.5.}....................
Boot0004* Generic Usb Device VenHw(99e275e7-75a0-4b37-a2e6-c5385e6c00cb)
Boot0005* CD/DVD Device VenHw(99e275e7-75a0-4b37-a2e6-c5385e6c00cb)
Boot0006* UEFI: PXE IPV6 Realtek PCIe GBE Family Controller
PciRoot(0x0)/Pci(0x1c,0x0)/Pci(0x0,0x0)/MAC(9c5a4489dd99,0)/IPv6([::]:<->[::]:,0,0)..BO
Boot0007* UEFI: PXE IPV4 Realtek PCIe GBE Family Controller
PciRoot(0x0)/Pci(0x1c,0x0)/Pci(0x0,0x0)/MAC(9c5a4489dd99,0)/IPv4(0.0.0.00.0.0.0,0,0)..BO
Boot0008* opensuse
HD(1,GPT,9f60665e-5479-407c-9b92-4c63a175ad8f,0x800,0x82000)/File(\EFI\OPENSUSE\GRUBX64.EFI)..BO
$
So BootCurrent is set to opensuse-secureboot. But when I start my PC, it starts
Windows Boot Manager.
But as I said, if I press [F12] at start and selecting opensuse-secureboot
directly, it starts.
