Bug 94459 [Undo] - should refactoring undo work when text undo limit is 0?
Refactoring undos are not showing up in the package explorer undo menu when the text undo limit is set to 0. Technically the refactoring operation should be permitted on the workspace undo context history. The history should just be removing the text context from the operation. One could argue this is a correctly working "feature" but need to check why it's happening and resolve the behavior as a bug or document as expected outcome.
bundles/org.eclipse.core.commands/src/org/eclipse/core/commands/operations/DefaultOperationHistory.java
*/
	private List redoList = Collections.synchronizedList(new ArrayList());
	/**
	 * the list of operations available for undo, LIFO
	 */
	private List undoList = Collections.synchronizedList(new ArrayList());
	/**
	 * a key that is used to synchronize access between the undo and redo
	 * history
	 */
	final Object undoRedoHistoryKey = new Object();
	/**
	 * An operation that is "absorbing" all other operations while it is open.
	 * When this is not null, other operations added or executed are added to
	 * this composite.
	 * 
	 */
	private ICompositeOperation openComposite = null;
	/**
	 * Create an instance of DefaultOperationHistory.
	 */
	public DefaultOperationHistory() {
		super();
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.core.commands.operations.IOperationHistory#add(org.eclipse.core.commands.operations.IUndoableOperation)
	 */
	public void add(IUndoableOperation operation) {