CSS Hyperlinks aren't working for the project that are not the WTP ones (when a project has no Module Core Nature ("org.eclipse.wst.common.modulecore.ModuleCoreNature")).

For such projects we cannot find according CSS file. This is a limitation in o.j.t.jst.web.kb.PageContextFactory.getFileFromProject(String, IFile).

See JBIDE-17726 on how to get an example of non-working Hyperlinks on CSS classes