BlackCloud.7480

I just got a Sonnet eGFX Breakaway Kit in the mail today. Hooked it up to my MacBook Pro Early 2015 13" (256 gig SSD), and it seems to working. "About this Mac" reports "Radeon RX 580 8 GB" under Graphics and I receive nice scores under Cinebench, but it doesn't seem like the GW2 Mac Client is picking up the card. As I understand it, by default any fullscreen GL application that's on the connected monitor should be processed through the eGPU. Am I missing something?