Details are explained there
How can I debug why the grid has empty rows when I have this renderer being assigned to the column?
You can get your hands dirty with the GWT Debugger, but it’s probably way easier to skip the addon and just use the stock ComponentRenderer https://vaadin.com/docs/v8/framework/components/components-grid
@quirky-zebra is it possible to mark grid objects boolean field through the Component Renderer, rendering the checkbox?
Sure just add a Checkbox.