Disable Microsoft Office 2013 Border Shadow with PowerShell

DisableBorder.ps1

Add-Type -TypeDefinition @"
using System;
using System.Runtime.InteropServices;

namespace Utilities {
  public static class Display {

    private const uint WM_USER = 0x0400;
    private const uint WM_MSO  = WM_USER + 0x0900;
    private const uint WM_MSO_WPARAM_OMFRAMEENABLESHADOW = 0x0075;
    private const uint WM_MSO_LPARAM_SHADOW_DISABLED     = 0x0000;
    private const uint WM_MSO_LPARAM_SHADOW_ENABLED      = 0x0001;

    [DllImport("user32.dll", CharSet = CharSet.Auto)]
    private static extern IntPtr SendMessage(
      IntPtr hWnd,
      UInt32 Msg,
      IntPtr wParam,
      IntPtr lParam
    );

    public static void DisableShadows(IntPtr hwndOfficeApp) {
      SendMessage(
        hwndOfficeApp,
        (UInt32) WM_MSO,
        (IntPtr) WM_MSO_WPARAM_OMFRAMEENABLESHADOW ,
        (IntPtr) WM_MSO_LPARAM_SHADOW_DISABLED
      );
    }

    public static void EnableShadows(IntPtr hwndOfficeApp) {
      SendMessage(
        hwndOfficeApp,
        (UInt32) WM_MSO,
        (IntPtr) WM_MSO_WPARAM_OMFRAMEENABLESHADOW ,
        (IntPtr) WM_MSO_LPARAM_SHADOW_ENABLED
      );
    }
  }
}
"@

$hwnd = @(Get-Process winword)[0].MainWindowHandle
[Utilities.Display]::DisableShadows($hwnd)

I get:
Cannot convert argument "0", with value: "", for "DisableShadows" to type "System.IntPtr": "Cannot convert null to type
"System.IntPtr"."
At line:1 char:36

• [Utilities.Display]::DisableShadows <<<< ($hwnd)
  • CategoryInfo : NotSpecified: (:) [], MethodException
  • FullyQualifiedErrorId : MethodArgumentConversionInvalidCastArgument

How to enable by default "DisableShadow" ?

You can't: https://support.microsoft.com/en-us/help/2821007/how-to-disable-shadow-hwnds-in-office-2013-applications
"There is no user setting to disable these shadows."

Is there anyway to make it permanent?
Thanks

---

Still work with Office 2019 and O365, Just tried as I wrote this question. Seems the article above is already taken down and M$ have no intention to make it as an option for a default option. So Sad.