cf3: domain problems

The documentaion lists domain as a common control promise, but the example in 5.1.6

body common control
{
domain => "example.org";
}

generates the following

Constraint lvalue domain is not allowed in 'common' constraint body, near token 
'example.org"'

NB The quoting at the end of that message isn't quite right.

The documentation (5.2) also shows domain being used in 'body agent control', 
but domain is not listed as an agent control promise. Trying it gives a similar 
message to the one above.

Jim