I have noticed that web essentials for visual studio creates a .css.map file when compiling less. Does this mean it is possible to navigate from a selector in the css file back to the selector in the associated less file? If so how?
In VS 2013, if you enable LESS preview window, you can leverage Go To Definition command on a selector in preview to highlight the corresponding selector in LESS source. (via right-click context menu or press F12 in preview window -- see #809). When applicable, it will also load the @imported document, where the source is available.
On that note, there are precession issues with libsass' source-map. For that matter, it doesn't work well in SCSS editor.