/// WM_DWMNCRENDERINGCHANGED is called when the non-client area rendering status of a window has changed. Only windows that have set the flag DWM_BLURBEHIND.fTransitionOnMaximized to true will get this message.

struct DWM_BLURBEHIND

    public DWM_BLURBEHIND(bool enabled)

Structure DWM_BLURBEHIND

static extern void DwmEnableBlurBehindWindow(IntPtr hwnd, ref DWM_BLURBEHIND blurBehind);

Private Shared Sub DwmEnableBlurBehindWindow(ByVal hwnd As IntPtr, ByRef blurBehind As DWM_BLURBEHIND)

DWM_BLURBEHIND