...but but this is exactly what I said:As you said, "should". There is no means to have 3d acceleration without VMSGA in my case. You can select VBoxSVGA but when you reopen the settings of the VM, it has returned to VMSVGA.
6) remember that you will have to set VboxSVGA/3D acceleration each time you edit settings (memory settings are fine).
I don't this as a problem because once all is set up I don't need to edit VM clients setting. However if there is a need for editing, I will have to apply VboxSVGA 3D settings again (as I explained in my post above)