In less files, the first nested selector is highlighted incorrectly (highlighting = using user chosen fonts and colors). In the image below, it is displayed in blue (the same color as classes or attributes), not in orange (as selectors). Here is how it looks with my color settings:
All subsequent nested selectors are highlighted correctly. After changing the sequence (putting field.filter-wrapper after div.filter-help) the coloring also changes, so that div.filter-help will be displayed in blue - as the first nested selector.
Perhaps it is a bug?