One way around this is to add another field directly on top of the dropdown field. Set the new field to Companies::CompanyDescription and set its behavior to not enter in Browse Mode. Either set the dropdown field's text color to the same as the background (usually white) or set its font size to 500 so it will not be displayed. When you click on the combined fields, the dropdown list will display as usually. After you choose an item from the list, the description will be displayed in the top field.