public void addCellEditorListener(CellEditorListener listener) {
		if (cellEditorListeners.contains(listener)) {
			throw new IllegalArgumentException("Listener has already been added: " + listener);
		}
		cellEditorListeners.add(listener);
	}
Adds a listener to be notified when cell editing is canceled or completed.
@param listener The listener to add
@throws IllegalArgumentException if the listener has already been added
Ghidra/Framework/Docking/src/main/java/docking/widgets/DropDownTextField.java