>>Len,
>>The new value must exist in rowsource. Add it.
>>Cetin
>
>Thanks for the confirmation.
>
>Guessed that was what the answer was going to be - makes life unnecessarily complicated, I'll have to consider if there are better options, that don't involve modifying the rowsource.

But modifying the rowsource is easy.

*Combo.lostfocus
With thisform
  If ascan(.myArray,this.DisplayValue)=0
    Dimension .myArray[alen(.myArray)+1]
    .myArray[alen(.myArray)]=this.DisplayValue
    This.NumberOfElements = alen(.myArray)
  Endif
Endwith

Actually I prefer another alternative. I almost all the time use SQL as rowsource and add to my cursor.
Cetin