In Object Designer for that Reference List you need to create an output template.
1. Double click the reference list, then in right hand window scroll down to find Templates then open the Output Attributes
2. Select the fields you want to see when you drop the list down.
In window manager open the web window you are using and select your reference list then on the properties set the Attribute Template under Configurable Properties (WebAccess) to the one you created in Object Designer.
The listing of a reference list which is used in Dropdown controls in windows cannot be sortet!
A case  at LANDesk has reveiled that this is a known issue which has been given problem number: 5818.
It has currently been given a low priority to be fixed in a future release.