Thx Joacim, u've enlighten me
OK, now got another problem, After creating the window, I want
to programmatically close it. I've use various methods like
PostMessage,SendMessage including DefWindowProc with the
message WM_DESTROY or WM_CLOSE. But it never close until
another msg or event occurs, i.e I move my mouse over the form.

Really donno where's da prob...