Lazy loading option allows loading items in lists/libraries on demand. That helps to speed up and improve the loading items process in the lists/libraries, especially in case of large numbers of items in the list/library.
The option is available on the display form on the List/Library configuration panel and can be used with or without 'Use as Sub item' option enabled.
On the New/Edit forms Lazy loading option is disabled if 'Use as Sub item' option is enabled.
If the option 'Lazy loading' is enabled on the form (display form) it works in the following way:
- When you open the form only the top-level folder will be loaded first.
- Items inside the folder are loaded when the user navigates to it or scrolls it down.
This will decrease the loading time for libraries on the form.
NOTE: There is some limitation of using the option:
- The evaluation result of the sublists/sublibraries placeholders (like Count, Sum, etc...) depends on the items number that has been loaded at this time
- Group By: grouping may not work properly
- Count on the view for the sublists/sublibraries will work as default SharePoint count (not recursive)