Use this property to let the SpellingChecker class use a custom ignore list.
There are two types of ignore lists, the default which is Application wide. That is the ignore list which you always are using after constructing a instance of the SpellChecker class is the Application Ignore list.
Even if two instances are constructed of the SpellingChecker class then by default both will point to the same ignore list.
The CurrentIgnoreListID property and the GetUniqueIgnoreList function can be used to assign custom non application wide ignore lists to the class instance. Such ignore lists are useful for example if each document in the application should have its own ignore list.