Hi
First i believe that the inbox icon need an alternate icon if you have unread messages (i didn't see anything that would allow one to see they recived a private message, but i may have missed it)

also the icon isn't displayed when you use the site on mobile phone (using mobile version of the site) and if you switch to computer version, enter the inbox and switch back to mobile version the layout gets thrown out of order

Android version 5.0

Using chrome version 52.0.2785.124