Bug 94438 [Undo] - javadoc - clarify operation remaining in history for undo/redo with INFO/WARNING
The javadoc for the IOperationHistory#undo(...) redo(...) methods is very explicit about the operation remaining in the history on CANCEL and ERROR status, and that it is moved between undo/redo histories when ok. Some minor clarifications: The lack of an explicit statement about INFO and WARNING makes one wonder what happens to the operation. It remains in the history in this case also... Technically, on OK status the operation is not guaranteed to move between the stacks. If it cannot redo after undoing, or cannot undo after redoing, it won't be transferred to the other stack, but in effect will be removed from the history.
bundles/org.eclipse.core.commands/src/org/eclipse/core/commands/operations/IOperationHistory.java
* 
	 * @throws ExecutionException
	 *             if an exception occurred during redo.
	 */
	IStatus redoOperation(IUndoableOperation operation,
			IProgressMonitor monitor, IAdaptable info)
			throws ExecutionException;
	/**
	 * <p>
	 * Remove the specified operation approver from the list of operation
	 * approvers that are consulted before an operation is undone or redone.
	 * </p>
	 * 
	 * @param approver
	 *            the IOperationApprover to be removed. Must not be
	 *            <code>null</code>. If an attempt is made to remove an
	 *            instance which is not already registered with this instance,
	 *            no operation is performed.
	 */
	void removeOperationApprover(IOperationApprover approver);
	/**
	 * <p>
	 * Remove the specified listener from the list of operation history
	 * listeners.
	 * </p>
	 * 
	 * @param listener
	 *            The IOperationHistoryListener to be removed. Must not be
	 *            <code>null</code>. If an attempt is made to remove an
	 *            instance which is not already registered with this instance,