GridLayout Properties
Wrapping Column: (NaN means there's no limit)
Wrapping Width: (NaN means use the diagram's viewport width)
Cell Size: (NaN x NaN means use a cell size big enough to hold any node)
Spacing: (the minimum space between the nodes)
Alignment: Position Location
Arrangement: LeftToRight RightToLeft

For information on GridLayout and its properties, see the GridLayout documentation page.