[c2]: extra newline inserted when posting a reply in IE11 [finish #66099032] 

0. Use IE11 (don't know about other IE versions -- this didn't happen in Chrome)
1. Go to a topic detail page
2. Click in the reply box
3. Type a character
4. Notice that an extra newline has been inserted before your character. https://www.pivotaltracker.com/story/show/66099032