Interview Question: MessageBox in FieldEdit

For last few weeks I have been busy doing quite a lot of interviews for recruiting new members for my team. One of the common question I used to ask during the interview is this.

Question: I have a field on a page and there is a Field Edit PeopleCode associated with this record field. PeopleCode contains only one statement

MessageBox(0,"",0,0,"Message from FieldEdit");

However when the user changes the field value on the page, this message box is not displayed. What could be the reason? 

 I was surprised to hear different wrong answers. Few of those funny answers are listed below.

• One of the junior consultant with around 3 years of experience in PeopleSoft told me that FieldEdit would be triggered only if the field is required. (I guess he derived it from the fact that FieldEdit is triggered after the system edits are validated)
• One of them (with 5 years of experience) answered that there should be some code in FieldChange otherwise FieldEdit wouldn't be executed.
•  Another gentleman said he is not sure about the reason but he would try to do PeopleCode trace and find out what the issue is.

So what is your answer? Isn't it obvious? :wink