I am using Google Keyboard 4.1 (intentionally an older version) that works flawlessly everywhere and was working also before I updates my Opera browser 2-3 weeks ago. The bug start appearing with that version of Opera with the new URL bar. When I try to type in the URL bar - the keyboard works fine, but if I try to click on a input box in a site - it is 50/50, sometimes the keyboard shows, sometimes not and it really annoying. When it shows I can type normally. I didn't have issues with showing the keyboard before that version of the browser.