UpdateLayeredWindow in pywin32

[livibetter]

I have found the cause

"Please note that after SetLayeredWindowAttributes has been called,
subsequent UpdateLayeredWindow calls will fail until the layering
style bit is cleared and set again."
from http://msdn2.microsoft.com/en-us/library/ms632599.aspx#layered

But I still can't use winxpgui.UpdateLayeredWindow, Now I am using
ctypes to enable calling UpdateLayeredWindow, and this works.