The columnWidth property is ignored unless the layout property is set to table.
Reference_Syntax.columnWidth = “measurement | -1 [, [, measurement | -1 ] ]”
The value of this property is a set of space-separated tokens. Each token must be a valid measurement or -1. The presence of a measurement causes the corresponding column to be set to that width. The presence of -1 causes the corresponding column to grow to the width of the widest content for that column across all rows of the table.
Form Model

columnWidths