Why is FlowRouter rerendering the whole layout?

if I remeber right, Flow Router wouldn’t rerender the whole layout if it stays on “the same route” (this was the behavior in Blaze - see this issue). For example, I’ve this route:

FlowRouter.route("/category/:catName", {


    action() {
        mount(Layout, {
            content: (<div>hello</div>)

This is my layout:

export class Layout extends Tracker.Component {

    render() {

        return (
            <div id="layout">

                <div className="bg-1"></div>

                <div className="content-box white z-depth-1">
                    <div id="start">
                       <a href="/category/test">sdsd</a>


So for example, if I move from /category/welcome to /category/test, the render() method is called again. So why do we have this difference between Blaze & React? As far as I know, FR should provide better rendering control and now we have 2 different behaviors on Blaze and React?

It’s possible that it was overlooked in react-mounter due to React being more performant on re-renders - the code for that is implemented in blaze-layout, not flow router (which doesn’t handle ui)