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:

• If the label is a single blank, any vertical space the text occupied inside the box is lost, but any vertical space the label occupied above the box is not lost.
• If the label is a null string, all vertical space is lost, whether above the box or inside it.

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

 }

}