You'll need to explicitly navigate to the input box _designated_ for using a search engine. If I'm accidentally pasting what I thought was a URL but actually i

You'll need to explicitly navigate to the input box _designated_ for using a search engine. If I'm accidentally pasting what I thought was a URL but actually is some other text in the paste buffer in the combined input box, that text is already sent to the search engine (provided suggestions are enabled, which they are by default). If I do the same in the split URL/search box situation, and paste it in the URL box, it would at most look into the browser's history, keeping the input local.