This bug seems to affect Safari and Chrome. I don't have access to IE/Edge to test, but it isn't reproducible in Firefox. If you start a new Quick Reply by clicking the smilie button and then picking a smilie from the list, it works fine for the first time. But once you've posted your reply, if you try to start another new Quick Reply with a smilie in the same post without refreshing, although you can click the smilie button to see the list of smilies, nothing happens if you then click a smilie from the list - it's not inserted. You have to type some text in the box before you are able to insert a smilie when composing your second (or third, etc) Quick Reply in the same post, unless you refresh the page. I'm assuming this is a bug because you don't have to type some text in the box before you are able to insert a smilie when you're making your first reply.