Bug 123316 [Undo] - API BEHAVIOR - should always place a successfully undone/redone op on the redo/undo history
bundles/org.eclipse.core.commands/src/org/eclipse/core/commands/operations/IOperationHistory.java
* </p>
	 * 
	 * @param context
	 *            the context to be checked
	 * @return <code>true</code> if there is an undoable operation,
	 *         <code>false</code> otherwise.
	 */
	boolean canUndo(IUndoContext context);
	/**
	 * <p>
	 * Dispose of the specified context in the history. All operations that have
	 * only the given context will be disposed. References to the context in
	 * operations that have more than one context will also be removed. A
	 * history notification for the removal of each operation being disposed
	 * will be sent.
	 * </p>
	 * 
	 * @param context
	 *            the context to be disposed
	 * @param flushUndo
	 *            <code>true</code> if the context should be flushed from the
	 *            undo history, <code>false</code> if it should not
	 * @param flushRedo
	 *            <code>true</code> if the context should be flushed from the
	 *            redo history, <code>false</code> if it should not.
	 * @param flushContext
	 *            <code>true</code> if the context is no longer in use and
	 *            references to it should be flushed.
	 */
	void dispose(IUndoContext context, boolean flushUndo, boolean flushRedo,