The SIZE of a grid is the number of characters across that you want to be visible in the grid. This is measured using the grid's default font. The LINES of a grid is the number of rows you want to be visible. Note that this is not the same as the number of records in the case where a record occupies more than one row. Normally, you should ensure that the LINES setting of a grid is an even multiple of the number of rows per record.
Space is added as needed to accommodate the grid's scroll bars and any border or grid lines.