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
/**
	 * An operation is to be opened or closed for execution. (value is 1).
	 */
	public static final int EXECUTE = 1;
	/**
	 * An operation is to be opened for undo. (value is 2).
	 */
	public static final int UNDO = 2;
	/**
	 * An operation is to be opened for redo. (value is 3).
	 */
	public static final int REDO = 3;
	/**
	 * An undo context that can be used to query the global undo history. This
	 * context is not intended to be assigned to operations. Instead, it is used
	 * for querying the history or performing an undo or redo on the global
	 * history.
	 */
	public static final IUndoContext GLOBAL_UNDO_CONTEXT = new GlobalUndoContext();
	/**
	 * An operation info status describing the condition that there is no
	 * available operation for redo.
	 */
	public static final IStatus NOTHING_TO_REDO_STATUS = new OperationStatus(
			IStatus.INFO, OperationStatus.DEFAULT_PLUGIN_ID, OperationStatus.NOTHING_TO_REDO, 
			"No operation to redo", null); 
	/**