SubtitleEdit: Get context menu using ExpressionTree

        private static Action<object, string> TokenProvider;

        private static Action<object, string> BuildTokenProvider(object control)
        {
            if (TokenProvider != null)
            {
                // NOTE: once this is contructed, if you try to invoke it using other type of control it will throw exception
                return TokenProvider;
            }
            Type ctrlType = control.GetType();
            var objParam = Expression.Parameter(typeof(object), "control");
            var objValueParam = Expression.Parameter(typeof(string), "value");
// convert the given object to control type to allow accesing "SelectedText" property
            var convertExpr = Expression.Convert(objParam, ctrlType);
            var propExp = Expression.Property(convertExpr, "SelectedText");
            var binaryExp = Expression.Assign(propExp, objValueParam);
            TokenProvider = Expression.Lambda<Action<object, string>>(binaryExp, objParam, objValueParam).Compile();
            return TokenProvider;
        }

        public static ContextMenu GetRegExContextMenu(object control)
        {
            TokenProvider = TokenProvider ?? BuildTokenProvider(control);
            var cm = new ContextMenu();
            var l = Configuration.Settings.Language.RegularExpressionContextMenu;
            cm.MenuItems.Add(l.WordBoundary, delegate { TokenProvider(control, "\\b"); });
            cm.MenuItems.Add(l.NonWordBoundary, delegate { TokenProvider(control, "\\B"); });