We don't currently make use of GWT's CellTable in Errai UI. It seems we need lazy (re-)loading and pagination support in ListWidget.
Do you see the performance issue in both DevMode and production mode?
We also have an unmerged pull request (still missing a test) using IndexedPanel (https://github.com/errai/errai/pull/82). IndexedPanel will improve the performance when adding/removing items but probably not when initially displaying a big number of rows.
Are you interested in providing a solution and sending us a pull request for this?
Yes, the performance issue is in production as well.
We can try the IndexedPanel once it's available, but as you mentioned, it probably won't help much on the initial display of the table.
We can take a look at adding pagination support to the ListWidget and sending a pull request.
Thanks, Carl. That'd be great!