Thanks for contacting Syncfusion support.
Query: “ In addition, how do I know when the user has re-ordered columns? Is there an event I can hook into? && I answered my own question...”
We are glad to hear that you have resolved the query on your own. Yes you can use OnActionComplete event and GetColumns() method to achieve your requirement. This (OnActionComplete) event will be triggered whenever certain action like paging, reorder, filtering, sorting, etc. get completed.
Refer our UG documentation for the list of events support in EjsGrid along with API reference.
Please get back to us if you have further queries.