Device view can be found under the Lab settings button to the left of the Lab toolbar.
There are three ways to view devices:
Single: The single will cause only a single device to be displayed at one time. Devices will need to be selected in the Device Menu to be displayed.
Multiple: The multiple option will cause all devices that are currently switched on to be displayed. The scroll bar can be used view them all.
Pop-up: The pop-up option can be used to have each device appear in it’s own window.