code: function isInsideOpenIsolatedNode (editorSession, surfaceManager) {
        if (surfaceManager) {
          let sel = editorSession.getSelection()
          let surface = surfaceManager.getSurface(sel.surfaceId)
          if (surface) {
            let isolatedNodeComponent = surface.context.isolatedNodeComponent
            if (isolatedNodeComponent) {
              return isolatedNodeComponent.isOpen()
            }
          }
        }
      }
docs: NOTE: this gets called whenever props or state is updated. Particularly, when this surface is co-focused, i.e. it has a child surface which is focused, and the child surface is inside a ('closed') IsolatedNodeComponent, then it is important to turn-off contenteditable, as otherwise the cursor can leave the isolated area..