When constructing them, you specify which group they belong to. You can reuse
existing groups (accessed through $special->getFilterGroup), or create your own
(ChangesListBooleanFilterGroup or ChangesListStringOptionsFilterGroup).
If you create new groups, you must register them with $special->registerFilterGroup.
When constructing them, you specify which group they belong to. You can reuse
existing groups (accessed through $special->getFilterGroup), or create your own
(ChangesListBooleanFilterGroup or ChangesListStringOptionsFilterGroup).
If you create new groups, you must register them with $special->registerFilterGroup.