Within the Guided Business Rules Language Editor, errors occurred with enumeration select boxes disappearing. This took place when the enumeration widget was defined with an external data-source. The Label, that shows the current value, was not updating to show the value of the constraint when the remote call completed. This in turn did not allow the selection of a value from the list. This issue has been resolved by ensuring the enumeration widget redraws itself correctly when the asynchronous call to retrieve data completes.