Bug 88352 Operation supports leaks contexts via action handler
I20050315-1100 Susan, this is a different leak from the one that I reported. Test Case: 1. open text editor 2. close text editor ==> DefaultUndoManager is leaked due to undo/redo actions handlers still holding on to the context.
bundles/org.eclipse.core.commands/src/org/eclipse/core/commands/operations/DefaultOperationHistory.java
* the list of {@link IOperationApprover}s
	 */
	protected List approvers = new ArrayList();
	/**
	 * a map of undo limits per context
	 */
	private HashMap limits = new HashMap();
	/**
	 * the list of {@link IOperationHistoryListener}s
	 */
	protected List listeners = new ArrayList();
	/**
	 * the list of operations available for redo, LIFO
	 */
	private List redoList = new ArrayList();
	/**
	 * the list of operations available for undo, LIFO
	 */
	private List undoList = new ArrayList();
	
	/**
	 * an operation that is "absorbing" all other operations while
	 * it is open.  When this is not null, other operations added or
	 * executed are ignored and assumed to be triggered by the batching
	 * 
	 */
	private IUndoableOperation batchingOperation = null;
	
	/*
	 * (non-Javadoc)