Change environment - GC environment setup checkboxes

I use Grub Customizer "File->Change Environment" when I want to have a backup on USB flash drive. There are 2 checkboxes, one "[] /boot/efi" and the other "[] save this configuration. It is possible to "Apply" changes with these boxes unchecked. I wonder what these boxes do and what happens when we do check these boxes.

I searched and read pages with Grub Customizer install/config help, but didn't find any info about "Grub Customizer environment setup" form. I also searched FAQ here on launchpad.

This time I copied Ubuntu partition on sdb4 to another partition on sdb7.
Updated the grub start menu within grub-customizer so I could start Ubuntu on sdb7

Learned a lot doing so....

Started Ubuntu on sdb7 but it mounted "/" from sdb4 (dah!)
Changed fstab to mount sdb7 (gpt-id)

Still trying to figure it out , to change grub-cusomizer configuration so I can safely delete sdb4 without breaking the grub!

/dev/sdb3 is mounted as /boot/efi on both sdb4 and sdb7 (the copy)

I also changed /boot/efi/EFI/ubuntu/grub.cfg "search.fs.uuid" value (from sdb4s to sdb7s uuid) plus "hd1,gpt5 hd1, gpt5" to "hd1,gpt8 hd1, gpt8"

I am not sure (yet) when to delete sdb4 and still trying to figure out the Grub-customizer chnage environment dialog and its two checkboxes...

Update: (2024-03-24)
Finally I managed to delete the old Ubuntu partition , move the EFI partition to the end of deleted partition, extend the Windows 10 partition using the deleted partition space and run Ubuntu from new copied partition.

Still wondering about those checkboxes ;)

BTW: Trying to change environment to sdc (USB that holds Gparted-live) did not have any effect since the USB started with Gparted and not the grub menu. I also tried "Save to MBR..." to same USB flash drive and still get the Gparted menu at start and not the grub menu.

Thank you in advance

grub-customizer 5.2.4
Ubuntu 23.10 updated 2024-03-22
vmlinuz-6.5.0-25-generic
Hp Folio 9470
mSata 256 GB
RAM 16 GB