loading master data!!!

I have been given the below form but here i cant understand the use of this checkbox named LoanCredit card number.
I am told that when user checks it then all master data will be displayed.......
does it mean that when i am entering some data in the database then the data will not not appear in the dropdownlist of the creditcard no. combobox automatically,
on checking the checkbox the creditcard no. which is saved in the database will be added in its dropdown list?
again when i uncheck it then again the dropdownlist of the combobox will become empty?
Actually i cant get the idea of using this checkbox..........
Any ideas.........
i need some help!!!
Attachment 72793

1. You can always look in the code to see what is performed, exactly, when the checkbox is checked or unchecked.
2. If there's no code written yet, and you are the person to write that code, your best bet is to ask the person who gives you the form to explain it.
I don't think anyone here can give you an answer except the person who designed that form.

I am told that when user checks it then all master data will be displayed.......

What would you have done if you have been given the form then?

any suggestions........

I would clarify what exactly the phrase "all master data will be displayed" means. What is the "master data"? Where does that "master data" come from? Where is that master data displayed? What should occur when the user check and then uncheck the checkbox?... These are the kind of questions that you need to ask the person(s) when you're unclear about something.

Don't make any assumptions when it comes to specifications.