public void addDropDownSelectionChoiceListener(
			DropDownMultiSelectionChoiceListener<T> listener) {
		choiceListeners.add(listener);
	}
Adds the caller to a list of subscribers who will be notified when selection changes.

@param listener the subscriber to be added
Ghidra/Framework/Docking/src/main/java/docking/widgets/DropDownMultiSelectionTextField.java