FastColoredTextBoxNS.InsertCharCommand.MergeLines C# (CSharp) Method

        internal static void MergeLines(int i, TextSource ts)
        {
            var tb = ts.CurrentTB;

            if (i + 1 >= ts.Count)
                return;
            tb.ExpandBlock(i);
            tb.ExpandBlock(i + 1);
            int pos = ts[i].Count;
            //
            /*
            if(ts[i].Count == 0)
                ts.RemoveLine(i);
            else*/
            if (ts[i + 1].Count == 0)
                ts.RemoveLine(i + 1);
            else
            {
                ts[i].AddRange(ts[i + 1]);
                ts.RemoveLine(i + 1);
            }
            tb.Selection.Start = new Place(pos, i);
            ts.NeedRecalc(new TextSource.TextChangedEventArgs(0, 1));
        }

        internal static void ClearSelected(FastColoredTextBox tb)
        {
            Place start    = tb.Selection.Start;
            Place end      = tb.Selection.End;
            int   fromLine = Math.Min(end.iLine, start.iLine);
            int   toLine   = Math.Max(end.iLine, start.iLine);
            int   fromChar = tb.Selection.FromX;
            int   toChar   = tb.Selection.ToX;

            if (fromLine < 0)
            {
                return;
            }
            //
            if (fromLine == toLine)
            {
                tb[fromLine].RemoveRange(fromChar, toChar - fromChar);
            }
            else
            {
                tb[fromLine].RemoveRange(fromChar, tb[fromLine].Count - fromChar);
                tb[toLine].RemoveRange(0, toChar);
                tb.RemoveLine(fromLine + 1, toLine - fromLine - 1);
                InsertCharCommand.MergeLines(fromLine, tb);
            }
            //
            tb.Selection.Start = new Place(fromChar, fromLine);
            //
            tb.needRecalc = true;
        }