In an input box you can pre-define the set of values to choose from. In this case, the input box consists of a list of currencies from the data model (from the CURRENCY field). The syntax needed to produce a drop-down list of values is to separate the values you want to use with semicolons. So this function:
Results in the following:
This is the list of values that are then shown in the input box.
@Terry Kavouras Thanks for the speedy reply Terry, however this isn't working for me!
Here is a screenie of my script (same as the salesforce one): http://i.imgur.com/HHaal33.png
Here is a screenie of my botched input box: http://i.imgur.com/E91QmvJ.png
And here is a link of my input box constraint settings: http://i.imgur.com/GE9K3Vx.png