Apply patch by Johannes Simon to improve usability of search bar:
"When a query is started, I think it's better not to delete the contents of the search box. Instead, the contents should be selected when a different search engine is chosen, so that the user can either start overwriting the text with a new search text right away, or hit enter and do the same search again with a different search engine. This btw is exactly the way it's done by Firefox' search bar.

Currently, I find it really annoying having to re-enter the text over and over again when I want to redo the search (either with the same search engine, or another)."