void CButtonST::OnEnable(BOOL bEnable) 
{
	CButton::OnEnable(bEnable);
	
	if (bEnable == FALSE)	
	{
		//CWnd*	pWnd = GetParent()->GetNextDlgTabItem(this);
		//if (pWnd)
		//	pWnd->SetFocus();
		//else
		//	GetParent()->SetFocus();
		CancelHover();
	} // if
} // End of OnEnable

HICON CreateGrayscaleIcon(HICON hIcon, COLORREF* pPalette);

HICON CButtonST::CreateGrayscaleIcon(HICON hIcon, COLORREF* pPalette)
{
	if (hIcon == NULL)
	{
		return NULL;
	}

	HDC hdc = ::GetDC(NULL);

	HICON      hGrayIcon      = NULL;
	ICONINFO   icInfo         = { 0 };
	ICONINFO   icGrayInfo     = { 0 };
	LPDWORD    lpBits         = NULL;
	LPBYTE     lpBitsPtr      = NULL;
	SIZE sz;
	DWORD c1 = 0;
	BITMAPINFO bmpInfo        = { 0 };
	bmpInfo.bmiHeader.biSize  = sizeof(BITMAPINFOHEADER);

	if (::GetIconInfo(hIcon, &icInfo))
	{
		if (::GetDIBits(hdc, icInfo.hbmColor, 0, 0, NULL, &bmpInfo, DIB_RGB_COLORS) != 0)
		{
			bmpInfo.bmiHeader.biCompression = BI_RGB;

			sz.cx = bmpInfo.bmiHeader.biWidth;
			sz.cy = bmpInfo.bmiHeader.biHeight;
			c1 = sz.cx * sz.cy;

			lpBits = (LPDWORD)::GlobalAlloc(GMEM_FIXED, (c1) * 4);

			if (lpBits && ::GetDIBits(hdc, icInfo.hbmColor, 0, sz.cy, lpBits, &bmpInfo, DIB_RGB_COLORS) != 0)
			{
				lpBitsPtr     = (LPBYTE)lpBits;
				UINT off      = 0;

				for (UINT i = 0; i < c1; i++)
				{
					off = (UINT)( 255 - (( lpBitsPtr[0] + lpBitsPtr[1] + lpBitsPtr[2] ) / 3) );

					if (lpBitsPtr[3] != 0 || off != 255)
					{
						if (off == 0)
						{
							off = 1;
						}

						lpBits[i] = pPalette[off] | ( lpBitsPtr[3] << 24 );
					}

					lpBitsPtr += 4;
				}

				icGrayInfo.hbmColor = ::CreateCompatibleBitmap(hdc, sz.cx, sz.cy);

				if (icGrayInfo.hbmColor != NULL)
				{
					::SetDIBits(hdc, icGrayInfo.hbmColor, 0, sz.cy, lpBits, &bmpInfo, DIB_RGB_COLORS);

					icGrayInfo.hbmMask = icInfo.hbmMask;
					icGrayInfo.fIcon   = TRUE;

					hGrayIcon = ::CreateIconIndirect(&icGrayInfo);

					::DeleteObject(icGrayInfo.hbmColor);
				}

				::GlobalFree(lpBits);
				lpBits = NULL;
			}
		}

		::DeleteObject(icInfo.hbmColor);
		::DeleteObject(icInfo.hbmMask);
	}

	::ReleaseDC(NULL,hdc);

	return hGrayIcon;
}

HICON CButtonST::CreateGrayscaleIcon( HICON hIcon )
{
	static COLORREF defaultGrayPalette[256];
	static BOOL bGrayPaletteSet = FALSE;

	if (hIcon == NULL)
	{
		return NULL;
	}

	if (!bGrayPaletteSet)
	{
		for(int i = 0; i < 256; i++)
		{
			defaultGrayPalette[i] = RGB(255-i, 255-i, 255-i);
		}

		bGrayPaletteSet = TRUE;
	}

	return CreateGrayscaleIcon(hIcon, defaultGrayPalette);
}

When building this code, one gets a compiler warning:
BtnST.cpp(19) : warning C4005: 'BS_TYPEMASK' : macro redefinition c:\Program Files\Microsoft Visual Studio .NET 2003\Vc7\PlatformSDK\Include\WinUser.h(8749) : see previous definition of 'BS_TYPEMASK'

I have also encountered the same warning.

Is it because of the MS-Platform SDK that we have installed, as the warning is because the constant is already defined in the WinUser.h in the Platform SDK.

Is this inevitable, or there's something wrong that we're doing?

The problem isn't just that it is being defined again, but that it is being defined again with a different value. In BtnST.cpp BS_TYPEMASK is defined as SS_TYPEMASK, on my current development system SS_TYPEMASK is defined as 0x0000001FL; however before this line BS_TYPEMASK was 0x0000000FL. So the general questions are:

• Should it be 0x1F or 0x0F?
• Should it use the SDK's value if defined, but 0x1F if not?
• Why SS_TYPEMASK (a Static Control Style value) for BS_TYPEMASK (a Button Style value)?

//BtnST.cpp
LRESULT CButtonST::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
{
    switch (message)
    {
    case WM_NCPAINT:
        {
            m_bmpBk.DeleteObject();
            m_dcBk.DeleteDC();
            m_dcBk.m_hDC=NULL;
        }
    }
    return CButton::WindowProc(message, wParam, lParam);
}
void CButtonST::OnLButtonDown(UINT nFlags, CPoint point)
{
	GetParent()->Invalidate();
	CButton::OnLButtonDown(nFlags, point);
}

wBmpWidth -= (wBmpWidth%4);             // width is 4 byte boundary aligned.

dwBmpWidth  = (dwBmpWidth+3) & ~3;      // 4 bytes padding