Hi,
There are some issues with the scrolling in the multiple group select control.
Sometimes, the 'A-Z wheel' gets out of sync with the items as you can see in the video below:
http://1drv.ms/1LwBmQY
Also, sometimes, a small drag completely changes the items as you can see in the video below:
http://1drv.ms/1LwBFen
Both those issues happens with Chrome and Safari on iOS 8.
Best regards,