Element attributes – PB Docs 2017

Select Edit Attributes from the pop-up menu for elements to edit
an existing attribute or add a new one. The attributes that display
include all the default attributes for the elements with any template
changes applied. The name attribute (and in some cases the class
attribute) used to identify the element is omitted and cannot be
changed.

You can change or delete the default attribute values or add new
ones. Controls or expressions can also be referenced for element
attribute values.

For each attribute specified, you can select a control reference
from the drop–down list or enter a literal text value. A literal text
value takes precedence over a control reference. You can also use the
expression button to the right of the Text box to enter an
expression.

The expression button and entry operates similarly to DataWindow
object properties in the Properties view. The button shows a green
equals sign if an expression has been entered, and a red not-equals sign
if not. A control reference or text value specified in addition to the
expression is treated as a default value. In the template, this
combination is stored with the control reference or text value, followed
by a tab, preceding the expression. For example:

When you finish modifying element attributes and you click OK,
only changes are stored in the template. Default attributes that are
deleted are added in the template and marked with an empty value.