Just discovered that flash resets the author-time letter spacing of a dynamic textfield when the textfield’s text is set in ActionScript.
To maintain the authortime letter spacing settings of the textfield, you need to record the textfield’s textformat, set the text, and then reset the textfield’s textformat to what it was. For example, if your textfield’s instance name is test:
var fmt:TextFormat = test.getTextFormat();
something to check is that if the textfield does not contain any text, the author-time TextFormat letter spacing property is not recorded. So if you don’t want your textfield to contain any text, make sure the textfield contains at least one space to ensure it maintains its author-time TextFormat letter spacing property.