Each component of the page has a title-bar with the name if it's class (e.g. SLStoryViewer), 4 tools and one switch.

Clicking on the small icons to the right of the component title bring up the following tools:

1. smalltalk code browser and editor
2. object property viewer
3. CSS editor for that component
4. source code viewer

1. R: the defined renderer
2. S: the HTML source code: e.g. the story dated 12 March in the screenshot has been switched to source code mode
3. D: DOM display

This in-browser level of web-developement is light-years ahead of anything else as far as I know.