I just created a ticket for this as well...
I currently have 2 monitors. The primary computer is connected via HDMI. The laptop on the dock is connected via DVI...there are 4 cables in total (2 going to each monitor - 1 cable from each of the 2 devices). In any case, even if it is connected, it does not allow me to utilize the secondary with 2 screens - even when the physical connections are there.
This should be looked into!
Edit: As an added example to this. I am a programmer myself. I absolutely NEED, not even want, dual monitor support. It is proven for added efficiency. With that being said, say I open Chrome on one monitor. Switch to the other monitor, open explorer. It opens in Monitor #1...so essentially even if the other monitor is there, I am constrained to that one monitor. Ultimately if we have the hardware as it should be, the software should function as a true KVM.
I even changed the input on the monitors to see if I switched to the alternate display if that would work and it did not. So I think it would be nice to understand what the developers intentions were with respect to this HUGE bug.