DropdownMenu.ClearHeaderItems

Description

Clears all header items from the menu.

using UnityEditor;
using UnityEditor.UIElements;
using UnityEngine;
using UnityEngine.UIElements;

public class ContextMenuWindow : EditorWindow
{
    [MenuItem("My/Context Menu Window")]
    static void ShowMe() => GetWindow<ContextMenuWindow>();

    Texture2D icon1;
    Texture2D icon2;
    Texture2D icon3;

    void CreateGUI()
    {
        var contextMenuContainer = new VisualElement();
        contextMenuContainer.style.flexGrow = 1;
        contextMenuContainer.AddManipulator(new ContextualMenuManipulator(e =>
        {
            e.menu.AppendHeaderAction(icon1, a => Debug.Log("My Action 1 Works"), a =>
            {
                a.tooltip = "Icon 1";
                return DropdownMenuAction.Status.Normal;
            });
            e.menu.AppendHeaderAction(icon2, a => Debug.Log("My Action 2 Works"), a =>
            {
                a.tooltip = "Icon 2";
                return DropdownMenuAction.Status.Normal;
            });
            e.menu.ClearHeaderItems();
            e.menu.AppendHeaderAction(icon3, a => Debug.Log("My Action 3 Works"), a =>
            {
                a.tooltip = "Icon 3";
                return DropdownMenuAction.Status.Normal;
            });
            e.menu.AppendAction("My Menu Item Action", a => Debug.Log("My Menu Item Action Works"), DropdownMenuAction.Status.Normal);
        }));

        var icon1Field = new ObjectField()
        {
            label = "Icon 1",
            objectType = typeof(Texture2D)
        };
        icon1Field.RegisterValueChangedCallback(e => icon1 = (Texture2D)e.newValue);
        var icon2Field = new ObjectField()
        {
            label = "Icon 2",
            objectType = typeof(Texture2D)
        };
        icon2Field.RegisterValueChangedCallback(e => icon2 = (Texture2D)e.newValue);
        var icon3Field = new ObjectField()
        {
            label = "Icon 3",
            objectType = typeof(Texture2D)
        };

        icon3Field.RegisterValueChangedCallback(e => icon3 = (Texture2D)e.newValue);

        contextMenuContainer.Add(icon1Field);
        contextMenuContainer.Add(icon2Field);
        contextMenuContainer.Add(icon3Field);

        rootVisualElement.Add(contextMenuContainer);
    }
}