This is not a new request, but the original is locked (probably due to age). I have quite a few (11 to be exact) TitleBar buttons, and I would like to be able to separate or group them.
The original request is here, and the hope was to have the feature added into the 3.2 release, but it still doesn't appear to be added as of version 3.3.
It's still on our list, but unfortunately we can't guarantee a timeline. We'll have another look at it to see if it's something we can get into the final version of 3.4.0.