React: Removing widget does not working

Hello, Gridstack.js is very very interesting package, everything works, **BUT!** if I try add removing widgets in to React project from github demo, it start begin works little unstable ... widgets is removed, but block behind widget still exists, can moves and resize. What I do wrong? 

https://codesandbox.io/p/sandbox/gridstack-js-67gzwx

Thanks!