doc UPDATE clarify subtree parsing validation
diff --git a/src/parser_data.h b/src/parser_data.h
index 537d6d4..20ab860 100644
--- a/src/parser_data.h
+++ b/src/parser_data.h
@@ -159,7 +159,8 @@
data will not work correctly. */
#define LYD_PARSE_SUBTREE 0x400000 /**< Parse only the current data subtree with any descendants, no siblings.
Also, a new return value ::LY_ENOT is returned if there is a sibling
- subtree following in the input data. */
+ subtree following in the input data. Note that if validation is requested,
+ only the newly parsed subtree is validated. */
#define LYD_PARSE_WHEN_TRUE 0x800000 /**< Mark all the parsed nodes dependend on a when condition with the flag
that means the condition was satisifed before. This allows for
auto-deletion of these nodes during validation. */