This sets the number of rows in the scrolling display.
Normally this is set to 40 rows (about a full screen worth of messages)
In the Free version you can choose from 10 to 50 rows.
In the Registered version you can choose from 5 to 1000 rows.
Note – The higher number of scrolling display rows you choose the longer it will take to update the display. Every new message that is displayed causes the grid to shuffle all the displayed messages and drop off the last message. This shuffling uses CPU time, the more rows to shuffle, the more CPU time is consumed.