I've had an odd issue where my address bar stops responding. I can type in it, but hitting enter doesn't go to that site, nor does the arrow key. Clearing the cache doesn't help, but restarting does. However, even after restarting, it will start doing that again eventually. The other buttons work, including refresh. The plugin buttons I have on the top bar are Youtube Flash Player, HTTPS Everywhere, uBlock, and Backward/forward History Dropdown.