The new awesome bar design rolled out to Firefox 48 release received some criticism, how about this? Latest Firefox 51 Nightly awesome bar shows one-off buttons at the bottom in drop down when you type something, by selecting one-off with your mouse –or you can also use tab key for that, which allows to switch between one-offs — for a search term, you can able to perform searches with different search engines right from the urlbar. For the selected one-off button, context menu offers ‘Search in New Tab’ and ‘Set as Default Search engine ‘options.

Firefox 51: You can now do one-off searches from awesomebar

Firefox 51 one-off searches awesomebar

You can find this in latest Nightly

READ: Mozilla removes the Old Search UI from Firefox

How to Restore Firefox’s Old Search UI and Preferences Window

With this new feature or change in place, you can able to do one-click searches right from awesome bar. Mozilla here uses one-off code they use for Search bar, for urlbar also.

For more details, check this bug 1180944