I’ve fixed the One-Click Reply, just click on the Preview/post-type-icon panel (nice idea btw, Tumblr) on the right of an notification to reply to a post.

You should get the update in a few hours. To get it manually:

1. Click on the X icon
2. Click on One-Click Reply
3. Click on Re-install / Manually Update this extension

Sorry for the delay, thanks for using XKit.