Text update listener

Hi
Is there any way to set a listener when a dynamic textboxs’ text is changed via:
textbox_txt.text ?

I have a class for my custom buttons and I would like to add this listener to check the size of the textbox and resize accordingly when the text is changed.

I realise that the best method would be to have a function in the class that changes the text and does the check all in one. Problem is - because we’re now localising it in loads of European languages I was never expecting to have to change the text size dynamically if the copy is too long. So to go and change it to behave like this would be a bit of a mission, so hopefully there is some sort of easier solution…

Maybe an ENTER_FRAME event that tests for the textboxts’ text to != “”