CoreLibs\Basic arrayDiff for full array diff

PHP array_diff only compares missing elements in the second and existing
in the first so a full diff is only achieved if compares both ways (a,b)
and (b,a)
This function uns a full compare and returns difference in an array

www/lib/CoreLibs/Admin/Backend.php

@@ -105,6 +105,7 @@ class Backend extends \CoreLibs\DB\IO
 
 	/**
 	 * set the language encoding and language settings
+	 * use $OVERRIDE_LANG to override all language settings
 	 * the default charset from _SESSION login or from
 	 * config DEFAULT ENCODING
 	 * the lang full name for mo loading from _SESSION login

www/lib/CoreLibs/Basic.php

@@ -1236,12 +1236,22 @@ class Basic
 			$path[] = $key_lookin;
 		} else {
 			foreach ($haystack as $key => $val) {
-				if (is_scalar($val) && $val === $needle && empty($key_lookin)) {
-					break;
-				} elseif (is_scalar($val) && !empty($key_lookin) && $key === $key_lookin && $val == $needle) {
+				if (is_scalar($val) &&
+					$val === $needle &&
+					empty($key_lookin)
+				) {
 					$path[] = $key;
 					break;
-				} elseif (is_array($val) && $path = Basic::arraySearchRecursive($needle, $val, $key_lookin)) {
+				} elseif (is_scalar($val) &&
+					!empty($key_lookin) &&
+					$key === $key_lookin &&
+					$val == $needle
+				) {
+					$path[] = $key;
+					break;
+				} elseif (is_array($val) &&
+					$path = Basic::arraySearchRecursive($needle, $val, $key_lookin)
+				) {
 					array_unshift($path, $key);
 					break;
 				}
@@ -1380,6 +1390,21 @@ class Basic
 		return $merged;
 	}
 
+	/**
+	 * correct array_diff that does an actualy difference between two arrays.
+	 * array_diff only checks elements from A that are not in B, but not the
+	 * other way around.
+	 * Note that like array_diff this only checks first level values not keys
+	 * @param  array  $a array to compare a
+	 * @param  array  $b array to compare b
+	 * @return array     array with missing elements from a & b
+	 */
+	public static function arrayDiff(array $a, array $b): array
+	{
+		$intersect = array_intersect($a, $b);
+		return array_merge(array_diff($a, $intersect), array_diff($b, $intersect));
+	}
+
 	/**
 	 * search for the needle array elements in haystack and return the ones found as an array,
 	 * is there nothing found, it returns FALSE (boolean)