If the label attribute of a boxed row or column is either blank ( " " ) or null ( "" ), the box encloses the cluster but no text is shown.
A single blank does not appear as a space in the box. However, there is a difference in the way blank and null labels are laid out:
In the following DCL code, the top lines of the boxes around the first two columns are guaranteed to line up (with the same Y location), and the top line of the box around the third column is guaranteed to have no spacing above or below it, except for the default margins:
: row { : boxed_column { label = "Some Text"; } : boxed_column { label = " "; // single blank: the default } : boxed_column { label = ""; // null string } }