Firefox 18
Firefox now supports Retina displays for the main page content (but not favicons). Many of the images in the user interface are not high-resolution. This makes it even more obvious that Firefox doesn’t have a fully native Mac interface. The Advanced toolbar button in the Preferences window would have been high-resolution if the developers had used NSImageNameAdvanced
instead of their own image, and likewise for the standard help button image and the back/forward arrows in the bookmarks list.