C2018-031 added CheckAndFixBorderArrays() that will correct the table border arrays only if needed, prior to editing a table.

PROMS/Volian.Controls.Library/VlnFlexGrid.cs

@@ -1356,6 +1356,7 @@ namespace Volian.Controls.Library
 			Rectangle bounds = e.Bounds;
 			int row = e.Row;
 			int col = e.Col;
+			MyBorders.CheckAndFixBorderArraySize(this.Rows.Count, this.Cols.Count, GridLinePattern.Single); // C2018-031 check the cell border arrays
 			CellRange cr = GetMergedRange(row, col);
 			GridLinePattern topSide = MyBorders.HorizontalLines[cr.r1,cr.c1];
 			GridLinePattern rightOfTopSide = cr.c2 == Cols.Count - 1 ? GridLinePattern.None : MyBorders.HorizontalLines[cr.r1, cr.c2 + 1];