A possibility would be to exclude the symmetry constraint from grouping. I have implemented this and pushed to my branch.
The result is this: Now the symmetry icons are shown as you request.
We are not in a hurry. Get some sleeping and let me know your impressions...Other than the offset I think they look great - it's much more helpful for the user if the constraint symbol isn't always displayed horizontally.
I'd still like to compile your branch and try your changes but that won't be for another 8 hours or so because I'm getting sleepy.