You toggle the CSS visual layout aids on/off: View > Visual Aids
I also make extensive use of Firebug in Firefox to see which rule is affecting which element in the layout.
When you say there's no CSS tree, are you referring to the CSS Panel in DW or the Code in Code View or something else?
In the CSS styles panel. In the video it shows they can selected and easily renamed or attributes changed or drag the hierarchy. However it seem to work like MX instead. No tree, just a list, cannot rename, or drag etc.
I do have the CSS view outlines enabled but nothing. Here's a link to the home page which I hand coded the body for CSS and none of it shows up in DWCS4 unless I go to live view and then I cannot edit or make changes. I have to do it by hand as I did in MX.
Can you post a screenshot of what you're seeing in DW?