Customizing the metamodel > Keywords for USRPROPS > ALLOW_COPY
  
ALLOW_COPY
The ALLOW_COPY keyword, which is implemented only for KEY TEXT properties, enables you to copy the property value: right‑click it, and then click Copy. Without it, the property depiction is read-only, so the edit control would be unavailable, and you cannot copy it.
Example
DEFINITION My Definition
{
...
PROPERTY "Property" { KEY EDIT TEXT LENGTH 2000 ALLOW_COPY }
...
}
See also
Keywords for USRPROPS