Specifies the layer or layers to which the shape is assigned.
Layer assignment is specified based on the zero-based index of layers for the page. If a shape is assigned to more than one layer, each layer index appears separated by a semicolon.
Optional string. Represents a unit of measure. The default is STR. For details about STR, see Units of measure.
Optional string. Represents the element's formula. This attribute can contain one of the following strings: "someFormula" if the formula exists locally, "No Formula" if the formula is locally deleted or blocked, or "Inh" if the formula is inherited.
If the attribute is not present, the element's formula is a simple constant, for example, <element>5</element>.
Optional string. Indicates that the formula evaluates to an error. The value of Err is the current value (an error message string); the value of the element is the last valid value.
Optional string. Represents the null string condition for a string cell value. In some cases it is helpful to distinguish between an empty string cell null and a null string cell value. This attribute is used to distinguish between these forms of an empty value.