After updating to reactable 0.3.0 from version 0.2.3, my tables suddenly seemed to have much more whitespace between individual cells. My code didn't change. It looks like the culprit is .rt-td-inner, which has extra padding and was introduced in commit d1ecacd (I assume this is in reactable.css. My old code just had a div <div class="rt-td rt-align-center"> with the content of the cell inside. In the new version, this div now first contains a <div class="rt-td-inner"> which contains the actual content of that cell.
I assume I can probably just fix it by setting padding to 0 for .rt-td-inner? I may have missed it, but shouldn't this have been documented as a breaking change?