This is the answer that appears on the FAQ's for PAF4 on the internet at www.familysearch.org/PAF
Also, uninstalling and reinstalling the PAF4 program will clear all the drop-down list boxes. This process clears the Registry.
If you are experienced you can go to the Registry and edit out the names from whatever list you desire.
The note is very important. Hope this helps.
Q: How do I get rid of names, dates, and places from the drop-down lists on the Edit Individual screen?
A: Highlight the item you want to remove, and press the Delete key on your keyboard. Both the text in the field and the item on the drop-down list will be deleted.
Note: This will remove items from the drop-down list during the current session. If you exit the program and run it again, any items you deleted will be in the list again. To remove them permanently you must add the same number of new items as the number of items you delete. For example, if you remove two items from the list, you must then add two items by typing them in the field. This usually occurs as a natural result of adding more records to your file.