Reverse video highlighting oddity under grub EFI 64-bit

[meta tech]

Hi,

I compiled grub2 from bzr for EFI 64-bit and installed it.
The command line mode works normally, but the menu selection has some
graphical oddity.
When a line is selected, its characters should normally be video reversed.
However, instead of that, each normal letter is replaced by two dark
grey solid character boxes (each has the size of the character box of
a single character).
Each space character is replaced by a middle grey solid character box
(the colour is correct for the video reversed mode).
When moving up one entry, the entry that becomes unselected stays with
the dark grey solid boxes and is not redisplayed in non-video reverse
mode.
When moving down one entry, the entry that becomes unselected comes
back to the normal non-video reverse mode.

Apart from the visual problem, the menu entries work fine.
I installed grub in a separate directory using the instructions on
http://grub.enbug.org/TestingOnMacbook
Version 1.98 has not the problem.

I hope you can visualise my explanation.
If you wish more information, do not hesitate to ask.

Regards,

metatech