Suggestion: A "Notes" layer with toggle and tooltip functionality.

It would be cool to have a layer dedicated to instructions, and/or a "tooltip" property for individual nodes, similar to how one can show custom titles per node. This could be helpful in complex workflows, building the documentation into the workflow itself and helping folks to learn the tool faster.

One could place items into that layer --- either Note nodes or Img loader nodes that currently exist, or some new sorts of nodes (f/e, a video link node perhaps that allowed inclusion of a video embed code).