private void richEditControl_PopupMenuShowing(object sender, PopupMenuShowingEventArgs e)
{
    if ((e.MenuType & RichEditMenuType.TableCell) != 0)
    {
        // Remove the "Paste" menu item:
        e.Menu.RemoveMenuItem(RichEditCommandId.PasteSelection);

        // Disable the "Hyperlink..." menu item:
        e.Menu.DisableMenuItem(RichEditCommandId.CreateHyperlink);

        // Create a RichEdit command, which inserts an inline picture into a document:
        IRichEditCommandFactoryService service = (IRichEditCommandFactoryService)richEditControl.GetService(typeof(IRichEditCommandFactoryService));
        RichEditCommand cmd = service.CreateCommand(RichEditCommandId.InsertPicture);

        //Create a menu item for the new command:
        RichEditMenuItemCommandWinAdapter menuItemCommandAdapter = new RichEditMenuItemCommandWinAdapter(cmd);
        RichEditMenuItem menuItem = (RichEditMenuItem)menuItemCommandAdapter.CreateMenuItem(DevExpress.Utils.Menu.DXMenuItemPriority.Normal);
        menuItem.BeginGroup = true;
        e.Menu.Items.Add(menuItem);

        // Insert a new item into the Richedit popup menu and handle its click event:
        RichEditMenuItem myItem = new RichEditMenuItem("Highlight Selection", new EventHandler(MyClickHandler));
        e.Menu.Items.Add(myItem);
    }
}

Private Sub richEditControl_PopupMenuShowing(ByVal sender As Object, ByVal e As PopupMenuShowingEventArgs) Handles richEditControl.PopupMenuShowing
    If (e.MenuType And RichEditMenuType.TableCell) <> 0 Then
        ' Remove the "Paste" menu item:
        e.Menu.RemoveMenuItem(RichEditCommandId.PasteSelection)

        ' Disable the "Hyperlink..." menu item:
        e.Menu.DisableMenuItem(RichEditCommandId.CreateHyperlink)

        ' Create a RichEdit command, which inserts an inline picture into a document:
        Dim service As IRichEditCommandFactoryService = DirectCast(richEditControl.GetService(GetType(IRichEditCommandFactoryService)), IRichEditCommandFactoryService)
        Dim cmd As RichEditCommand = service.CreateCommand(RichEditCommandId.InsertPicture)

        'Create a menu item for the new command:
        Dim menuItemCommandAdapter As New RichEditMenuItemCommandWinAdapter(cmd)
        Dim menuItem As RichEditMenuItem = CType(menuItemCommandAdapter.CreateMenuItem(DevExpress.Utils.Menu.DXMenuItemPriority.Normal), RichEditMenuItem)
        menuItem.BeginGroup = True
        e.Menu.Items.Add(menuItem)

        ' Insert a new item into the Richedit popup menu and handle its click event:
        Dim myItem As New RichEditMenuItem("Highlight Selection", New EventHandler(AddressOf MyClickHandler))
        e.Menu.Items.Add(myItem)
    End If
End Sub

public Form1() {
    InitializeComponent();
    this.richEditControl1.PopupMenuShowing += richEditControl1_PopupMenuShowing;
}
private void richEditControl1_PopupMenuShowing(object sender, DevExpress.XtraRichEdit.PopupMenuShowingEventArgs e) {
    var item = e.Menu.Items[AIIntegrationLocalizer.GetString(AIIntegrationStringId.MenuItemAIAssistant)];
    if (item != null) {
        item.Caption = "My AI Helper";
        item.ImageOptions.SvgImage = this.IconOptions.SvgImage;
    }
}

Public Sub New()
    InitializeComponent()
    AddHandler Me.richEditControl1.PopupMenuShowing, AddressOf richEditControl1_PopupMenuShowing
End Sub

Private Sub richEditControl1_PopupMenuShowing(ByVal sender As Object, ByVal e As DevExpress.XtraRichEdit.PopupMenuShowingEventArgs)
    Dim item = e.Menu.Items(AIIntegrationLocalizer.GetString(AIIntegrationStringId.MenuItemAIAssistant))
    If item IsNot Nothing Then
        item.Caption = "My AI Helper"
        item.ImageOptions.SvgImage = Me.IconOptions.SvgImage
    End If
End Sub

richEditControl.Options.Behavior.ShowPopupMenu = DocumentCapability.Disabled;

richEditControl.Options.Behavior.ShowPopupMenu = DocumentCapability.Disabled