* <ul>
* <li>#MDB_CURRENT - replace the item at the current cursor position.
* The \b key parameter must still be provided, and must match it.
- * So must \b data if using sorted duplicates (#MDB_DUPSORT).
+ * If using sorted duplicates (#MDB_DUPSORT) the data item must still
+ * sort into the same place. This is intended to be used when the
+ * new data is the same size as the old. Otherwise it will simply
+ * perform a delete of the old record followed by an insert.
* <li>#MDB_NODUPDATA - enter the new key/data pair only if it does not
* already appear in the database. This flag may only be specified
* if the database was opened with #MDB_DUPSORT. The function will