<apex:actionRegion /> is interesting and somewhat ignored tag in Visualforce. Tag is ignored, because Visualforce documentation is not in depth, to explain the real utility of this tag. So this post explains some stuff around action region to make it easy for developers to understand.

Special thanks to @RajendraOgra for sharing his findings and information around this tag with me.

Read More: https://abhinav.fyi/deep-dive-into-visualforce-tag/