RedrawTaskbar.csx

#!/usr/bin/env dotnet-script
// https://github.com/vurdalakov/scripttools/

using System.Runtime.InteropServices;

var taskbarHandle = FindWindow("Shell_TrayWnd", null);

if (IntPtr.Zero == taskbarHandle)
{
    Console.WriteLine("Cannot find taskbar window");
    return;
}

// approach 1

SendMessageTimeout(taskbarHandle, WM_SETTINGCHANGE, UIntPtr.Zero, IntPtr.Zero, SMTO_ABORTIFHUNG, 1000, out _);

// approach 2

ShowWindow(taskbarHandle, SW_HIDE);
ShowWindow(taskbarHandle, SW_SHOW);

// approach 3

InvalidateRect(taskbarHandle, IntPtr.Zero, true);
UpdateWindow(taskbarHandle);

private const UInt32 HWND_BROADCAST = 0xFFFF;
private const UInt32 WM_SETTINGCHANGE = 0x001A;
private const UInt32 SMTO_ABORTIFHUNG = 0x0002;
private const Int32 SW_HIDE = 0;
private const Int32 SW_SHOW = 5;

[DllImport("user32.dll", SetLastError = true)]
private static extern IntPtr FindWindow(string lpClassName, string lpWindowName);

[DllImport("user32.dll", SetLastError = true)]
private static extern Boolean ShowWindow(IntPtr hWnd, Int32 nCmdShow);

[DllImport("user32.dll", SetLastError = true, CharSet = CharSet.Auto)]
private static extern IntPtr SendMessageTimeout(IntPtr hWnd, UInt32 Msg, UIntPtr wParam, IntPtr lParam, UInt32 fuFlags, UInt32 uTimeout, out IntPtr lpdwResult);

[DllImport("user32.dll")]
private static extern Boolean InvalidateRect(IntPtr hWnd, IntPtr lpRect, Boolean bErase);

[DllImport("user32.dll")]
private static extern Boolean UpdateWindow(IntPtr hWnd);