[AS2/CS4] how to tell when text is loaded?


I have a scrollbar that is getting the height from the dynamic text field.
my problem is that for a brief moment before the text is loaded the field is too small for a scrollbar, so when the text does load and it requires to be scrolled, there is no scrollbar!

my question is: how can you tell when your text is loaded before the scrollbar tries to determine the height of the scrolled content?

any help would be greatly appreciated!! this is driving me nuts.
thanks in advance!