I was wondering if there are any plans to add line-based editing to the grid component similar to what is currently available in the Vaadin 8 grid.
This feature has not yet been implemented as you have noticed, there is feature request about it in our issue tracker here: https://github.com/vaadin/vaadin-grid-flow/issues/135 At the moment workarounds are either to use details row and have mini form to edit there, or render components in Grid.