After working further with the disappearing import problem I have found a few situations where FB3 strips out imports and then reports an error because you dont have the import it just removed.
One is where you just use the class in a cast as in: IStyleClient(x).getStyle(...) Another is using mx_internal almost anywhere. It is so bad that I have one class that currently just wont compile. So... anyone know how to turn off the automatic organisizing of imports? tks

