New Post: Formula issue after worksheet copy

        private static readonly Regex R1C1Regex = new Regex(
            //@"(?<=\W)([Rr]\[?-?\d{0,7}\]?[Cc]\[?-?\d{0,7}\]?)(?=\W)" // R1C1
            //+ @"|(?<=\W)([Rr]\[?-?\d{0,7}\]?:[Rr]\[?-?\d{0,7}\]?)(?=\W)" // R:R
            //+ @"|(?<=\W)([Cc]\[?-?\d{0,5}\]?:[Cc]\[?-?\d{0,5}\]?)(?=\W)"); // C:C
             @"(?<=\W)([Rr](\[-?\d{0,7}\])?[Cc](\[-?\d{0,7}\])?)(?=\W)" // R1C1
            + @"|(?<=\W)([Rr](\[-?\d{0,7}\])?:[Rr](\[-?\d{0,7}\])?)(?=\W)" // R:R
            + @"|(?<=\W)([Cc](\[-?\d{0,5}\])?:[Cc](\[-?\d{0,5}\])?)(?=\W)"); // C:C