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
* <code>INFO</code>, etc.) are not specifically interpreted by the
	 * history. The operation will remain in the history and the returned status
	 * is simply passed back to the caller. For all severities other than
	 * <code>OK</code>, listeners will receive the
	 * <code>OPERATION_NOT_OK</code> notification instead of the
	 * <code>REDONE</code> notification if the redo was approved and
	 * attempted.
	 * </p>
	 * 
	 * @throws ExecutionException
	 *             if an exception occurred during redo.
	 * 
	 */
	IStatus redo(IUndoContext context, IProgressMonitor monitor, IAdaptable info)
			throws ExecutionException;
	/**
	 * <p>
	 * Redo the specified operation. The redo of the operation is subject to
	 * approval by any registered {@link IOperationApprover} before it is
	 * attempted.
	 * </p>
	 * 
	 * @param operation
	 *            the operation to be redone
	 * @param monitor
	 *            the progress monitor to be used for the redo, or code>null</code>
	 *            if no progress monitor is provided
	 * @param info
	 *            the IAdaptable (or <code>null</code>) provided by the
	 *            caller in order to supply UI information for prompting the