The Engines panel lists some engines in bold face and some in normal face. When you use a bold-face engine, Noflail Search sends the query to a Web API provided by the engine, obtains results as an XML data structure, and displays those results in its Results panel. When you use a normal-face engine, Noflail Search runs the query on the engine's Web site and shows the page of results produced by the engine in a pop-up window. If you use a bold-face engine, after the results have been displayed in the results panel you can click on the icon or name of the engine in the title bar of the Results panel to run the query on the engine's site and see the resulting Web page in a pop-up window.
For some engines, you can specify a site restriction or a language restriction using a Site box or a Language box located above the Query box. (These boxes are shown only when they can be used with the engine present in the Engine box.) For example, you can enter "wikipedia.org" in the Site box to restrict your results to Wikipedia pages, or "Italian" in the "Langauge" box to restrict your results to pages written in Italian. Notice that the language restriction is independent of your country/language shown in the orange bar at the very top of the display. Notice also that search engines that support a language restriction are not always able to determine correctly the language that a page is written in.
You can visit the Web site of any engine in a pop-up window by clicking on the engine when the query box is empty and there are no site or language restrictions.