When viewing an Active Directory entry objectGUID attributes are not displayed, and it is also not possible to edit them. Same for objectSid, both have the same syntax OID. The entry editor just shows "Invalid Data" for them.
The attributes have binary values. They could be displayed either in hex format (and the hex format can be used in searches as well, with a backslash in front of every two hex digits), or using the preferred Microsoft format, which is just the hex format shuffled and delimited with dashes.
(I found this in version 1.3, but this is not listed as a released version)