You can make a copy of a query by holding down the Control key and the Shift or Alt key (on Windows) or the Command key (on the Mac) while dragging. If the query has a corresponding result set displayed in the Results panel, the two copies can be used to keep track of different positions within the result set.
You can also drag a query from the Search History and drop it into the Query box. This has the effect of removing the query from the History, then entering it into the Query box and submitting it automatically. The query is then reinserted at the top of the Search History, and its results are shown in the Results panel. If the query has zero results, a zero-result analysis is shown in a box that appears at the bottom section of the left panel. Otherwise, if there are related queries, they are similarly shown in a box at the bottom of the panel.