- Have a look at how datagrid2 constructs it personal-settings to store a user’s own settings. Copy that to Mx8. Your idea how to do this likely matches the datagrid2’s version;
- For drag and drop, try and implement this after document-ready: https://react-dnd.github.io/react-dnd or one of these https://react-dnd.github.io/react-dnd/examples/sortable/simple/;
- Saving the new setting after a drag-and-drop action is easiest done with a separate button on the page.
Hope it works out for you.
Indeed. Now that the LTS version of Mx9 has been released I would indeed suggest the upgrade path. Might be less work.