I think it is a general problem. I have two monitors set as a large desktop. Elemental shows up on one screen, some parts of my desktop on the second one. If I want to scroll in Elemental, I move the mouse to the edge of the screen. It works on all edges but not between the two monitors. The mouse appears in the second window and thus it is not able to scroll to the direction of the secondary monitor.
This bug is not big, but there shall be some solution sooner or later so players with two monitors don't need to change the monitor configuration.