Add WorkFlowy-style notes/comment to a block

WorkFlowy have this nice feature where you can add a note to a block as seen in the picture. Would be very handy to add small comments to blocks.

In CheckVist it looks like this…

I have used the notes feature in CheckVist very intensively, but to be honest, I never liked the way they “visually pollute” the outline.

I would like it much better, if the notes were displayed in a sidebar to keep the structure of the outline clean.