First of all, yes i do have an ACTIVE DP to HDMI adapter and it works fine if i unplug my secondary monitor.
My plan with this was to use 2 monitors as extended desktop and have the third cable clone the main screen and run into my capture card.
This works fine if i only have the main monitor and the capture card via adapter connected but as soon as i plug in the second monitor everything is reset and the capture card disabled.
Both the Catalyst Control Panel and Windows detect the third "monitor" but i'm unable to activate it.
Running a VTX3D R9 280 X-Edition (not 280x) on Windows 10 with Catalyst 15.7.1
Monitor 1 HDMI, Monitor 2 DVI, Capture Card HDMI from the dp adapter (Club3D CAC-1053)