private static void SetWindowEffect(IntPtr window, AccentPolicy accent) { var accentStructSize = Marshal.SizeOf(accent); var accentPtr = Marshal.AllocHGlobal(accentStructSize); Marshal.StructureToPtr(accent, accentPtr, false); var data = new WindowCompositionAttributeData { Attribute = WindowCompositionAttribute.WCA_ACCENT_POLICY, SizeOfData = accentStructSize, Data = accentPtr }; PInvoke.SetWindowCompositionAttribute(window, ref data); Marshal.FreeHGlobal(accentPtr); }