Customizable Drag-drop ToolStrip

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ToolStripCustomPlus
{
    class UniqueString
    {
        public UniqueString(string sOriginal)
        {
            original = sOriginal;
            existings = new List<string>();
        }

        public UniqueString(string sOriginal, string[] Existings)
        {
            original = sOriginal; 
            existings.AddRange(Existings);
        }

        public void AddExisting(string sExisting)
        {
            existings.Add(sExisting);
        }

        public bool GetUniqueString(out string sUnique)
        {
            if (existings.Contains(original))
            {
                sUnique = original;
                return false;
            }  
            
            //remove brackets and contents
            string originalNoBracketSub = original;
            int nIndexOfLastOpenBracket = original.LastIndexOf("(");
            int nIndexOfLastCloseBracket = original.LastIndexOf(")");

            if ((nIndexOfLastOpenBracket != -1) &&
                (nIndexOfLastCloseBracket != -1) &&
                (nIndexOfLastOpenBracket < nIndexOfLastCloseBracket))
            {
                originalNoBracketSub = original.Remove(nIndexOfLastOpenBracket);
            }

            if (existings.Contains(originalNoBracketSub))
            {
                sUnique = originalNoBracketSub;
                return true;
            }  
            
            int nCopyNum = 2;
            while (existings.Contains(originalNoBracketSub + "(" + nCopyNum.ToString() + ")"))
            {
                nCopyNum++;
            }
            sUnique = originalNoBracketSub + "(" + nCopyNum.ToString() + ")";
            return true;
        }

        private string original;
        private List<string> existings;
    }
}