Hello, Simon,

Thank you for the provided feedback.

However, I would like to note that xml and JSON files are quite specific and they may contain different information that RadPropertyGrid wouldn't be able to store. We will consider the possible solutions when implementing this feature according to the internal mechanism of RadPropertyGrid.

If you need to load xml data, I think that it would be more suitable to use our RadTreeView control as it is specifically designed to work with hierarchical data and the xml structure is very similar to the tree-view. Please refer to the following help article: https://docs.telerik.com/devtools/winforms/controls/treeview/data-binding/binding-to-xml-data

I hope this information helps. If you need any further assistance please don't hesitate to contact me. 

Should you have further questions please let me know.

Regards,
Dess | Tech Support Engineer, Sr.
Progress Telerik