title: How to implement pager change event in Tapestry's grid
body: <p>How to implement pager change event in Tapestry's grid? I've read the documentation, but couldn't find the answer. So what I'm trying to do is, I want to reset the <code>selectedItem</code> to <code>null</code> everytime the selected page changing, and I noticed that actually setupRender() triggered, but I don't want to use it because it does a quite heavy process. There's no point to do this only for page changes. So is there any way to implement it specifically only for pager changes? Thank you. I'm using Tapestry 5.3.8 btw</p>