From 1353caec41c5836076128664108f7949fb34e777 Mon Sep 17 00:00:00 2001
From: Hans Schuijff <hans@dewitteprins.nl>
Date: Mon, 1 Feb 2021 20:20:42 +0100
Subject: [PATCH 1/2] Skip sort_structure method for single lesson save.

---
 includes/class-sensei-course-structure.php | 52 +++++++++++-----------
 1 file changed, 27 insertions(+), 25 deletions(-)

diff --git a/includes/class-sensei-course-structure.php b/includes/class-sensei-course-structure.php
index 1c8b5e2fee..71ac3fb370 100644
--- a/includes/class-sensei-course-structure.php
+++ b/includes/class-sensei-course-structure.php
@@ -772,37 +772,39 @@ private function validate_item_structure( array $raw_item ) {
 	 * @return array Sorted structure.
 	 */
 	public static function sort_structure( $structure, $order, $type ) {
-		usort(
-			$structure,
-			function( $a, $b ) use ( $order, $type ) {
-				// One of the types is not being sorted.
-				if ( $type !== $a['type'] || $type !== $b['type'] ) {
-					// If types are equal, keep in the current positions.
-					if ( $a['type'] === $b['type'] ) {
-						return 0;
+		if ( ! empty( $order ) 
+		&&  [0] !== $order ) {
+			usort(
+				$structure,
+				function( $a, $b ) use ( $order, $type ) {
+					// One of the types is not being sorted.
+					if ( $type !== $a['type'] || $type !== $b['type'] ) {
+						// If types are equal, keep in the current positions.
+						if ( $a['type'] === $b['type'] ) {
+							return 0;
+						}
+
+						// Always keep the modules before the lessons.
+						return 'module' === $a['type'] ? - 1 : 1;
 					}
 
-					// Always keep the modules before the lessons.
-					return 'module' === $a['type'] ? - 1 : 1;
-				}
+					$a_position = array_search( $a['id'], $order, true );
+					$b_position = array_search( $b['id'], $order, true );
 
-				$a_position = array_search( $a['id'], $order, true );
-				$b_position = array_search( $b['id'], $order, true );
+					// If both weren't sorted, keep the current positions.
+					if ( false === $a_position && false === $b_position ) {
+						return 0;
+					}
 
-				// If both weren't sorted, keep the current positions.
-				if ( false === $a_position && false === $b_position ) {
-					return 0;
-				}
+					// Keep not sorted items in the end.
+					if ( false === $a_position ) {
+						return 1;
+					}
 
-				// Keep not sorted items in the end.
-				if ( false === $a_position ) {
-					return 1;
+					return false === $b_position || $a_position < $b_position ? -1 : 1;
 				}
-
-				return false === $b_position || $a_position < $b_position ? -1 : 1;
-			}
-		);
-
+			);
+		}
 		return $structure;
 	}
 }

From 919be5530d2fe218eeed3bfb5229afc13bb6d3dc Mon Sep 17 00:00:00 2001
From: Hans Schuijff <hans@dewitteprins.nl>
Date: Mon, 1 Feb 2021 20:45:13 +0100
Subject: [PATCH 2/2] Fixed lint-errors (just some spaces).

---
 includes/class-sensei-course-structure.php | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/includes/class-sensei-course-structure.php b/includes/class-sensei-course-structure.php
index 71ac3fb370..aa9015e17a 100644
--- a/includes/class-sensei-course-structure.php
+++ b/includes/class-sensei-course-structure.php
@@ -772,8 +772,8 @@ private function validate_item_structure( array $raw_item ) {
 	 * @return array Sorted structure.
 	 */
 	public static function sort_structure( $structure, $order, $type ) {
-		if ( ! empty( $order ) 
-		&&  [0] !== $order ) {
+		if ( ! empty( $order )
+		&& [ 0 ] !== $order ) {
 			usort(
 				$structure,
 				function( $a, $b ) use ( $order, $type ) {