call a new window when a text item is click or tab to

I have a fair simple requirement but somehow I am not sure how to handle it.  Need some suggestion.

In EBS 11.5.10.2.  I have a requirement that when user tab into or click into a text item ( called full name ) field in window_1, it will pop up a new window - window_2.  The new window- window_2 has 2 text fields ( e.g. First name, last name ).  LOV are attached to the first name and last name fields.  When user finish select or type in the first and last name in window_2, click OK, the window_2 will be closed.    The firstname.lastname will be pass it back to the first window - window_1 and show it into full_name