What's the window style of IME pad?

[hh...@ai.kaist.ac.kr]

I'm making a hand writing recognition TSF like WinXP IME pad.

It works like WinXP IME pad but has a focus problem.

WinXP IME pad doesn't steal focus but When I click my TSF window it
steals focus.

I made some trick in message handler by
returning MA_NOACTIVATE for WM_WM_MOUSEACTIVATE.

After that it doesn't steal focus even though I write some characters.
I can also type characters by keyboard.(which means my tsf doesn't
steal keyboard focus)

But if I click the title bar or change size, it still steals focus.
THIS IS MY PROBLEM.

I think IME pad uses different window style.

Can anyone help me out?