- * Returns a list of selected columns. The list contains no duplicates but is
- * not necessarily ordered. It also may include columns hidden from the
- * current view. This returns a copy of the actual list, and changes to the
- * copy will not affect the selection.
+ * Returns a read-only view of the (possibly empty) list of selected columns
+ * <p>
+ * The list contains no duplicates but is not necessarily ordered. It also may
+ * include columns hidden from the current view. To modify (for example sort)
+ * the list, you should first make a copy.
+ * <p>
+ * The list is not thread-safe: iterating over it could result in
+ * ConcurrentModificationException if it is modified by another thread.