Scrolled text form with mask doesn't seems to work

Hi everybody,
I wonder if you could help me with this:
I have a MC with a text form with several input and combo boxes (flash <=> php) it as a scroll and it works fine, except when I put the MC under a mask.
It still scroll’s but nothing shows inside the input boxes when I type on it.
Is this “normal” procedure for flash or It’s a bug of some kind?

Thank’s