Can I have a video timeline stretched across 2 monitors so I have a much longer timeline to make editing much more efficiency.

I am trying to setup my external monitor 43" LG to stretch my timeline onto it from my iMac. I plan to use my iMac for accurate color and external for efficiency. I have done this in the past. When I try to stretch the the timeline it is there in a ghost image then disappears when I let go of of mouse click button.