I work with two monitors (WM 2.3.7): One with the device workflow, the other one with a second window showing the 3d preview.
When built, the 3d preview jumps back to the first monitor, leaving the second one blank. Any idea how to avoid this? Switching views does not help.
In the Preferences dialog, "Build Options" tab, make sure "On World Build:" is set to Nothing.
That did the trick, thank you :D