Use Tab key to select url from address bar history drop down
In chrome when I type in the address bar and it gives a list of suggestions dropping down from the address bar I can cycle through the suggestions with the tab key. In Vivaldi hitting tab from the address bar always moves focus to the next UI element, leaving the address bar and suggestions. Tab is more convenient in keyboards than down arrow, and the most common use case in address bar once you've started typing will be to go or select a suggestion. Navigating away via keyboard is less likely (but should still be possible via ESC then Tab to cancel the dropdown and then navigate, which already works). I'm on Vivaldi 1.0.303.52 (Beta) (32-bit) (using it for about 3 days so far).