@bebraw , are you interested if I submit a patch to lock the left columns using css sticky?

I wrote https://reactabular.js.org/#/examples/fixed-columns.

But a built in numberOfPinnedColumns might be user friendly.

It's technically easy (see https://stackoverflow.com/questions/15811653/table-with-fixed-header-and-fixed-column-on-pure-css).

Need extra sanity check code (IE11 does not support css sticky, so code should fail elegantly. some error report in console, maybe).