DX9 switching from full screen to window give wrong client area - c++

Question

Having a bit of a problem in my dx9 application.
When I switch back from Full screen to windowed mode using the code below the client area is not the right size, it's smaller.
The AdjustWindowRect function is doing its task correctly but SetWindowPos does not set the right window size. Perhaps I'm missing something. Any ideas .
if (d3dpp.Windowed && resChoice == resolutionchoice) return false; // already in window mode and same resolution
//MessageBox(NULL, L"switching to window", L"ERROR", MB_OK);
resChoice = resolutionchoice;
screenWidth = resolutionwidth[resChoice];
screenHeight = resolutionheight[resChoice];
d3dpp.BackBufferFormat = D3DFMT_UNKNOWN; // set the back buffer format to 32-bit
d3dpp.BackBufferWidth = screenWidth; // set the width of the buffer
d3dpp.BackBufferHeight = screenHeight; // set the height of the buffer
d3dpp.Windowed = true;
SetWindowLong(hWnd, GWL_STYLE, WS_OVERLAPPEDWINDOW); // WS_CAPTION | WS_SYSMENU | WS_VISIBLE | WS_MINIMIZEBOX );
// need to call SetWindowPos as well
string values;
RECT r = { 0,0,screenWidth,screenHeight };
AdjustWindowRect(&r, WS_OVERLAPPEDWINDOW, false);
values = std::to_string(r.left);
OutputDebugStringA("Adjust area = ");
OutputDebugStringA(values.c_str()); OutputDebugStringA(",");
values = std::to_string(r.top);
OutputDebugStringA(values.c_str()); OutputDebugStringA(",");
values = std::to_string(r.right);
OutputDebugStringA(values.c_str()); OutputDebugStringA(",");
values = std::to_string(r.bottom);
OutputDebugStringA(values.c_str()); OutputDebugStringA("\n");
SetWindowPos(hWnd, HWND_TOP, r.left, r.top, r.right - r.left , r.bottom - r.top, SWP_NOZORDER | SWP_SHOWWINDOW | SWP_FRAMECHANGED);//
//screenWidth = SCREEN_WIDTH;
//screenHeight = SCREEN_HEIGHT;
//windowXscale = 1;
//windowYscale = 1;
GetClientRect(hWnd, &r);
values = std::to_string(r.left);
OutputDebugStringA("Client area = ");
OutputDebugStringA(values.c_str()); OutputDebugStringA(",");
values = std::to_string(r.top);
OutputDebugStringA(values.c_str()); OutputDebugStringA(",");
values = std::to_string(r.right);
OutputDebugStringA(values.c_str()); OutputDebugStringA(",");
values = std::to_string(r.bottom);
OutputDebugStringA(values.c_str()); OutputDebugStringA("\n");
}

Answer 1

After some more searching discovered that if you use SetWindowPos and attempt to make a window that is bigger than the desktop or when returning from Full screen in this case, windows will send a message and the window size will be adjusted automatically to make it no bigger than the current desktop size.
Adding SWP_NOSENDCHANGING flag in the SetWindowPos api call stops this happening and the client size will be what you wanted.