The type or namespace name 'PaletteSet' could not be found after migrating to .NET 8.0

[r_nijkamp]

After running the Upgrade tool from Visual Studio 2022 my code for loading a usercontrol to a new toolpalette is failing.

I get the error The type or namespace name 'PaletteSet' could not be found (are you missing a using directive or an assembly reference?)

Before the upgrade the code was working fine and i had no error or missing reference.

According the developer docs, toolpalettes are part of Autodesk.AutoCAD.Windows 

When i add Using Autodesk.AutoCAD.Windows it gets greyed out and my code keeps the error.

Below a bare minimum project trying to load a palette. What am i missing?

using Autodesk.AutoCAD.Runtime;
using Autodesk.AutoCAD.Windows;
using System.Drawing;

namespace RN_ACADTOOLS
{
    public class MainClass
    {
        

        [CommandMethod("showmypalette")]
        public void ShowMyPalette()
        {
            createPallete();
        }


        public void createPallete()
        {

            string palleteName = "My-Palette";

            PaletteSet myPaletteSet = new PaletteSet(palleteName, new Guid("{E405F622-A37A-420C-BC18-16F0B1935A4A}"));

            myPaletteSet.Style = PaletteSetStyles.ShowAutoHideButton |
                                    PaletteSetStyles.ShowCloseButton |
                                    PaletteSetStyles.Snappable;

            myPaletteSet.Opacity = 100;

            myPaletteSet.Size = new Size(500, 400);
            myPaletteSet.MinimumSize = new Size(250, 200);

            myPaletteSet.Add(palleteName, new UCmain());
            myPaletteSet.Visible = true;
        }
    }
}

[norman.yuan · Accepted solution]

Have you added reference to acmgd.dll? Autodesk.AutoCAD.Windows.PaletteSet class is contained in acmdg.dll assembly.

[r_nijkamp]

I feel stupid for missing this reference.
Thanks for your reply.