Note: old_value field of #AtkPropertyValues will not contain a valid value. This is a field defined with the purpose of contain the previous value of the property, but is not used anymore.
old_value
The new value of the named property.
NULL. This field is not used anymore.
The name of the ATK property which has changed.
Note:
old_valuefield of #AtkPropertyValues will not contain a valid value. This is a field defined with the purpose of contain the previous value of the property, but is not used anymore.