MFC window maximized, but to wrong top coordinate

Sometimes, when I use ShowWindow(SW_SHOWMAXIMIZED), my MFC window is maximized, but it is not positioned at coordinates (0, 0), as it should, it is moved down, for around 30-40 pixels. Any tip on what might be 开发者_Python百科wrong?

I found the solution. In PreCreateWindow(CREATESTRUCT& cs), CREATESTRUCT was modified, like this

cs.style = WS_OVERLAPPEDWINDOW | WS_MAXIMIZE;

Apparently, this was causing wrong WINDOWPLACEMENT coordinates. When changed to:

cs.style = WS_OVERLAPPEDWINDOW;

with call to

ShowWindows(SW_MAXIMIZE)

Everything worked fine.