protected override void OnBeforeContextMenu(CefBrowser browser, CefFrame frame, CefContextMenuParams menuParams, CefMenuModel model)
{
model.InsertItemAt(model.Count > 0 ? 1 : 0, (int)CefMenuId.ReloadNocache, "Refresh");
model.AddSeparator();
model.AddItem(SHOW_DEV_TOOLS, "&Show DevTools");
model.AddItem(INSPECT_ELEMENT, "Inspect element");
CefMenuModel submenu = model.AddSubMenu(0, "Submenu Test");
submenu.AddItem((int)CefMenuId.Copy, "Copy");
submenu.AddItem((int)CefMenuId.Paste, "Paste");
submenu.SetColorAt(submenu.Count - 1, CefMenuColorType.Text, CefColor.FromArgb(Colors.Blue.ToArgb()));
submenu.AddCheckItem(0, "Checked Test");
submenu.SetCheckedAt(submenu.Count - 1, true);
submenu.AddRadioItem(0, "Radio Off", 0);
submenu.AddRadioItem(0, "Radio On", 1);
submenu.SetCheckedAt(submenu.Count - 1, true);
}