Patch Set 1: I would prefer that you didn't submit this

- "New Branch..." should be enabled on references like HEAD
- s/Rename/Rename.../ as it's opening a dialog
- I am wondering what would be a more consistent title than "Checkout", maybe "Branches" ? "Rename" "New Branch..." and "Delete" have nothing to do with checkout 
- I think the button for checkout should be labeled "Checkout" instead of "Ok"