Private Sub ComboBox6_DropButtonClick()

I have just realised that EACH time i Click on the DropDownButtonClick
Button,
I get a Duplicate populated LIST if Clicked on more than ONCE.

TO ONLY ever populate the LIST ONCE, where should i be placing the code ?
It is on Userform5.
The code is dependant upon other values chosen on the Userform, so it
therefore cannot be placed in the Userform.Initialize or Activate event.

Any Idea's, or am i stuck with it here ?

Corey....