For each class Win Runner learns a set of default properties Each default property is classified “Obligatory “ or “optional”

An obligatory property is always learned if it exists

An optional property is used only if the obligation properties do not provide unique identification of an object these optional properties are stored in a list . Win runner selects  the minimum number of properties from this list that are necessary to identify the object  it begins  with first property in the list , and continues , if necessary to add properties to the description until it obtain  unique  identification for the object