in IJC when you define the entity there is an option which allows you to choose if the field in a table has discrete number of values or not. But by far i have to yet to figure out how to use this attribute. The only time i see its effect is when i look at a cell with that field, clieck on it you will see all possible value. I thought the drop-down should appare in the query mode when you query that field ... but it does not do that. Am i right, ir is this something to be added
This drop-down is not implemented in query mode for forms. It's not a bad idea, I will add it to our improvements database.
You can still benefit from "drop-down" in query builder. If you press Ctrl+B query builder will appear and allows to choose from discrete field values for querying.
I suggested this a long time ago. Even better would be if no discrete values would be required, and a dropdown menu would appear in a query field showing the values already present in the table field, and an empty field at the top where a new query could be entered.