When I undock my mixerview to place it in my second monitor, the undocked window is nowhere to be found. I tried
- moving or minimizing  existing windows,
- recalling the mixer view through the menu and Alt+2
- checking menu option "Window"
but nothing helps. Only when I change to a screenset that shows my mixer again, the undocking works as it is supposed to. 
 
Is this a bug or am I doing something wrong?
 
 

open it in the dock, then move the dock to the second monitor.

Thanks, dragging and dropping the tab to my second monitor does the trick!

cool!