promethean ActivPanel Titanium Getting Started Manual page 40

When a student mirrors their screen with Touchback enabled, their device's screen will be framed in bright
green. This is an example of the student's computer screen:
Likewise, when mirroring a student device with Touchback enabled, this screen will also be framed in bright
green on your panel, as shown below for the screen in the top left quadrant:
With Touchback enabled, you may navigate connected devices in real time. Possible classroom examples
include becoming untethered, sharing applications or programs, allowing students to display work and
demonstrate learning, and more.