Check out the first attached screenshot (idea-unused-selector.png). IDEA marks the selector .config-item-shortcode-selecionado as unused, which is almost correct – this selector is never directly referenced in CSS or HTML code, but is dynamically added or removed using javascript, as show in idea-dynamic-selector.png. While I can't expect IDEA to figure out which javascript functions actually manipulate CSS selectors, I would be quite happy if it considering a selector used if it shows up in any string literal. This sounds like a good compromise to me.