One more thing I’d like to clear up it’s a dependent dropdown function. This is what it’s all about:
When the values of some dropdown are set and they depend on the selection of other dropdown or on the selection of values of another element of the form.
For example if you have a drop down (or pick-list) that stores a list of countries and another drop down that stores a list of cities; it is possible to show only cities of the selected country by marking the "city" drop down dependent on the "country" drop down. This is the brief description of how it works.
So I d like to prove the value of apps in regards to this function. We’ll see.