[ComVisible(true)]
public class AuthenticationOptions :
    RichEditNotificationOptions,
    IDisposable

<ComVisible(True)>
Public Class AuthenticationOptions
    Inherits RichEditNotificationOptions
    Implements IDisposable

using DevExpress.XtraRichEdit;
using DevExpress.XtraRichEdit.API.Native;
using DevExpress.XtraRichEdit.Services;
        void richEditControl1_DocumentLoaded(object sender, EventArgs e)
        {
            UpdateUserNameLoginCombo();
            richEditControl1.Options.Authentication.UserName = String.Empty;
        }
        private void UpdateUserNameLoginCombo()
        {
            cmbUserName.SelectedValueChanged-=cmbUserName_SelectedValueChanged;
            RangePermissionCollection rangePermissions = richEditControl1.Document.BeginUpdateRangePermissions();
            richEditControl1.Document.CancelUpdateRangePermissions(rangePermissions);
            List<String> users = new List<string>();
            foreach (RangePermission rangePermission in rangePermissions)
            {
                string userName = rangePermission.UserName;
                if (users.Contains(userName))
                    continue;
                if (!String.IsNullOrEmpty(userName))
                    users.Add(userName);
            }
            cmbUserName.Properties.BeginUpdate();
            cmbUserName.Properties.Items.Clear();
            cmbUserName.Properties.Items.Add(String.Empty);
            cmbUserName.Properties.Items.AddRange(users);
            foreach (MyUser user in myUserList) {
                if (!users.Contains(user.UserName)) cmbUserName.Properties.Items.Add(user.UserName);
            }
            cmbUserName.SelectedIndex = 0;
            cmbUserName.Properties.EndUpdate();
            cmbUserName.SelectedValueChanged += cmbUserName_SelectedValueChanged;
        }

        private void cmbUserName_SelectedValueChanged(object sender, EventArgs e)
        {
            string username = cmbUserName.SelectedItem.ToString();
            richEditControl1.Options.Authentication.UserName = username;
            MyUser myuser = myUserList.Find(s => s.UserName == username);
            richEditControl1.Options.Authentication.Group = (myuser != null) ? myuser.Group : String.Empty;

        }

Imports DevExpress.XtraRichEdit
Imports DevExpress.XtraRichEdit.API.Native
Imports DevExpress.XtraRichEdit.Services
        Private Sub richEditControl1_DocumentLoaded(ByVal sender As Object, ByVal e As EventArgs)
            UpdateUserNameLoginCombo()
            richEditControl1.Options.Authentication.UserName = String.Empty
        End Sub
        Private Sub UpdateUserNameLoginCombo()
            RemoveHandler cmbUserName.SelectedValueChanged, AddressOf cmbUserName_SelectedValueChanged
            Dim rangePermissions As RangePermissionCollection = richEditControl1.Document.BeginUpdateRangePermissions()
            richEditControl1.Document.CancelUpdateRangePermissions(rangePermissions)
            Dim users As New List(Of String)()
            For Each rangePermission As RangePermission In rangePermissions
                Dim userName As String = rangePermission.UserName
                If users.Contains(userName) Then
                    Continue For
                End If
                If Not String.IsNullOrEmpty(userName) Then
                    users.Add(userName)
                End If
            Next rangePermission
            cmbUserName.Properties.BeginUpdate()
            cmbUserName.Properties.Items.Clear()
            cmbUserName.Properties.Items.Add(String.Empty)
            cmbUserName.Properties.Items.AddRange(users)
            For Each user As MyUser In myUserList
                If Not users.Contains(user.UserName) Then
                    cmbUserName.Properties.Items.Add(user.UserName)
                End If
            Next user
            cmbUserName.SelectedIndex = 0
            cmbUserName.Properties.EndUpdate()
            AddHandler cmbUserName.SelectedValueChanged, AddressOf cmbUserName_SelectedValueChanged
        End Sub

        Private Sub cmbUserName_SelectedValueChanged(ByVal sender As Object, ByVal e As EventArgs) Handles cmbUserName.SelectedValueChanged
            Dim username As String = cmbUserName.SelectedItem.ToString()
            richEditControl1.Options.Authentication.UserName = username
            Dim myuser As MyUser = myUserList.Find(Function(s) s.UserName = username)
            richEditControl1.Options.Authentication.Group = If(myuser IsNot Nothing, myuser.Group, String.Empty)

        End Sub