On Linux Mint Cinnamon running Waterfox, there seems to be no way to access the search engine without the mouse, which defeats the whole purpose of this when there is already the upper-right dropdown. It highlights the first tab in the dropdown, but neither Shift+Tab nor Up actually put the cursor in the search engine; you can't type without first clicking there.

Unlike the original, the ported version is sometimes in the wrong order of recent opening.