When I code on a visualization in RStudio, I can see the code on the left and the graphic on the right. I get that this is harder to do with Observable, but the current solution involves constantly scrolling up and down to see the effect of code changes further down on the page. I found this rather annoying while trying Observable.
In some way this is even more annoying than to [Alt]-[Tabbing] between a code editor and a (hot reloading) browser preview, because it involves switching from keyboard to mouse.
Perhaps certain blocks can be made “sticky” so they are visible no matter where I scrolled to on the page. Or there’s an optional “side by side” view that I can scroll to a different position, just like the split view in Excel. My hunch is that sticky blocks are probably better performing, though.