Custom editors should be placed inside #if UNITY_EDITOR or Editor only asmdef.
Library\PackageCache\com.tonymax.nsprites.foundation@ebe6f264d8\Sorting\Editor\SortingLayerPropertyDrawer.cs(8,47): error CS0246: The type or namespace name 'PropertyDrawer' could not be found (are you missing a using directive or an assembly reference?)
Custom editors should be placed inside
#if UNITY_EDITOR
or Editor only asmdef.