Rated 5 out of 5 stars

In FireFox 43.0.2 in simple url bar mode, enter not work on first item in drop-down list and when caret at the end of URL. In previous version I use (most likely 42.0) enter key worked fine. See image: https://img-fotki.yandex.ru/get/6425/8555553.0/0_129226_c59e3411_orig.png

[Added]
Solution from https://addons.mozilla.org/ru/firefox/addon/oldbar/
Fix for this:
Change
browser.urlbar.unifiedcomplete = false
Check https://support.mozilla.org/en-US/questions/1099228