Data validation list - list doesn't show items from top

[Pwinkle]

I created a data validation range that is blank at the beginning and users
enter informtion into the range. They do not have to enter in all the cells
so the list created will include blank cells. When I test it the drop down
only shows from the top of the list if there is information in all cells. I
use the information to generate resource usage in MsProject, so I need the
blank cells to be blank. Any ideas on how to make the list show from the top
without entering something in the entire range (it works if I enter a space
in the blank cells, but then it generates information that cannot be copied
to MsProject).