Add windows 7 to grub2 boot menu

When grub2 loads there are Leap 15.0, and Windows 10 choices.
I also have an install of Windows 7.

Is there an easy way to add windows 7 to the grub2 configuration file(s)?
Or should I even consider it? I already use easyBCD to boot form initially.

Windows 10 and windows 7 on HDD 1 along with the system and a recovery partition.

Device     Boot     Start       End   Sectors   Size Id Type
/dev/sdb1  *           64    204863    204800   100M  7 HPFS/NTFS/exFAT
/dev/sdb2          208845 660242866 660034022 314.7G  7 HPFS/NTFS/exFAT
/dev/sdb3       660244480 661202943    958464   468M 27 Hidden NTFS WinRE
/dev/sdb4       661203270 976769071 315565802 150.5G  7 HPFS/NTFS/exFAT    **<<<<< WINDOWS 7 partition**

Leap 15.0 is on a second HDD

Disk /dev/sdc: 149 GiB, 160000000000 bytes, 312500000 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0xd0f4738c

Device     Boot     Start       End   Sectors Size Id Type
/dev/sdc1            2048  16771071  16769024   8G 82 Linux swap / Solaris
/dev/sdc2  *     16771072 100663295  83892224  40G 83 Linux
/dev/sdc3       100663296 205518847 104855552  50G 83 Linux
/dev/sdc4       205518848 312498175 106979328  51G 83 Linux

All OS’s must boot in the same mode to chain. If all boot the same method (EFI or MBR) then running Yast - boot loader and be sure that probe for other OS box is checked. Also the Windows systems must have fast boot set off and not use any special formatting or encryption. Be sure you make a change even if you change back in the boot loader section to make the program think a change was made if the box is already checked.

The probe for foreign OS box is checked in YaST. Win10 fast boot is off, I don’t know about Win7. Both boot from the Windows HDD MBR. No special formatting or encryption that I am aware of.
It is probably not worth the trouble since I use easyBCD. Was hoping maybe to get to the point of only using grub2, but I am not that comfortable with the linux things yet.
Better get on with finding out how to make my printer work(now that I am officially NOT a root user!) Am looking at a VM, and trying to find my WinXP 32 bit install CD/DVD.

Thanks for the response.

It is expected to work. To answer why it did not logs are required. If you are interested in answer, please provide output of (as root)

START_TIME=$(date +%s)
journalctl --no-pager --since @$START_TIME