private static int      fold(FastColoredTextBox aFCTB, int aStartLine)
        {
            for (int i = aStartLine; i < aFCTB.LinesCount; i++)
            {
                if (String.IsNullOrWhiteSpace(aFCTB[i].FoldingEndMarker) == false)
                {
                    return(i);
                }

                if (String.IsNullOrWhiteSpace(aFCTB[i].FoldingStartMarker) == false)
                {
                    int lEnd = fold(aFCTB, i + 1);
                    aFCTB.CollapseFoldingBlock(i);
                    i = lEnd;
                }
            }

            return(aFCTB.LinesCount);
        }