Is there a way to add a list items TreeView as a WebPart Property? Can you give me an overview on how to do this, knowing that the TreeView should contain selectable checkboxes that allow to retrieve the selected items.
I know that a custom property will be displayed automatically in the Property Pane if it’s of type bool, DateTime, enum, int, or string. But what if we want to add a TreeView, like in my case?
(I'm under SharePoint 2013)