RowLineTypes is an integer vector, whose length is normally equal to the number of rows in the Grid. Each element in RowLineTypes specifies an index into the GridLineFCol and GridLineWidth properties, thus selecting the colour and width of the horizontal grid lines.

For example, if RowLineTypes[1] is 3, the first horizontal grid line in the Grid is displayed using the colour specified by the 3^rd element of GridLineFCol, and the width specified by the 3^rd element of GridLineWidth.

Note that RowLineTypes is not ⎕IO dependent, and the value 0 is treated the same as the value 1; both selecting the first colour and line width specified by GridLineFCol and GridLineWidth respectively.

The default value of RowLineTypes is an empty numeric vector (⍬). If so, all horizontal grid lines are drawn using the first element of GridLineFCol and GridLineWidth.

A horizontal grid line is drawn along the bottom edge of its associated row. One pixel is drawn inside the row of cells; additional pixels (if any) are drawn between that row of cells and the next one below.