A dynamic combo-box is very similar to a lookup: in both cases a list of codes is retrieved by calling a business component on the server side.
Anyway, there are two main differences between them:
combo-box → show one only column (description)
lookup grid → can show any number of columns
combo-box → mustn’t be used to fetch a great degree of values (web app will crash on the client side)
lookup grid → no limit in the number of items
Therefore, it is essential not to use combo-boxes when the number of items exceeds a few hundreds of records.
