This attribute can be used to control the width of columns in a DCL
list control (list_box or
popup_list). The value of
this attribute has to be a string containing a space separated list
of integers. For historic reasons these integers are cumulative, it
is a list of increasing integers. Every integer adds the width of
the next column to the previous cumulative width. So to specify
four columns of width 5, use "5 10 15 20". Mind that there will be
a fifth column of remaining width, so perhaps the last integer is
not wanted.