Hello , i just had installed maya 2015 and so here are some few bugs for you to fix 
- the two screen below show the full size of the panel in maya, the resize is not possible, so to fixe that i had to tweak the script:
http://puu.sh/89gBK.jpg
http://puu.sh/89jug.jpg
2.the proxy mesh looks very odd in maya viewport : ( not sure waht can cause this issue ? viewport 2.0?)
http://puu.sh/89jH1.png
- now the most annoying bug i get with ART on each version of maya 2012, 2014 and now 2015
look at the previous screen ( http://puu.sh/89jH1.png ) and more particuliarly the background gradient set by default is remove every time I Build the final Rig.
i had to reset to default the main Color preferences settings that i had just set up with this new maya 2015 installation, so it no really productive.
You should try to set the gradient background in your preference if is not the case, so you could maybe reproduce this issue, if you don’t hav that problem with your viewport.
Nicolas