Gravity form not working

Thanks for reply.
Home page desktop form view is ok and select services from dropdown (http://prntscr.com/f9jbwe)
this is working fine in responsive mode at 320x480px device width (http://prntscr.com/f9jbz5)
but when i am select iphone6 or ipad from device list, the select is not working (http://prntscr.com/f9jc1b)
from here i am select devices for responsive view (http://prntscr.com/f9jc4t)

I am using Firefox developer edition and responsive mode show by pressing Ctrl+Shift+M
I had sent website admin access, please try it. Let me know for other info.
Please do this fast.
Thanks!