Purpose With ColumnWidth you can change the column width in a table control.
Examples ColumnWidth [Material] 8

ColumnWidth [Table.2,Material] 8

Format ColumnWidth [column] n

ColumnWidth [table,column] n

n is the new column width in the table display (number of characters). If the column contains cells that contain more than n characters, the cell can be scrolled.
The table name should be specified if there are 2 or more tables on the screen and the column name is not unique. You name the table by its title, if a table title is shown, or otherwise as Table, Table.2, … If you click on View->Screen elements in GuiXT you see the correct name of the table.

ColumnWidth [...] 0: If you specify width 0, then the column is not displayed but can be displayed again by the user with the mouse, contrary to ColumnSize [...] 0.

If the table is already customized by normal R/3 means, and you use GuiXT in addition, then the GuiXT script overrides.