R7500v1 QoS priorities not changeable?

I can't edit the priority of my devices.  Got it today because I have terrible internet and when multiple people are on the net, I get anywhere from 80 to 300 ping on League, and copious amounts of packet loss.  I really need QoS settings so I don't constantly get the short end of the bandwidth while two other family members are streaming in HD.  But when I enabled Dynamic QoS and went to the attached devices page, I can see the priorities of all the devices connected clearly (my PC is on low by default...) but when I click the checkbox and go to edit, there is no option to change the priority.  I'm pretty sure the priority is supposed to be a dropdown menu, but it's just plain text for me. 

Thanks in advance for any suggestions.