Apple AppleVision monitors (OS 7.1) - Manual (Page 6)

Using more than one monitor
If you have more than one monitor or video card attached to your computer, a
separate Monitors & Sound window appears on each monitor, and an
Arrange button automatically appears in the Monitors & Sound window on
your main monitor.
The options available in each Monitors & Sound window reflect the
capabilities of the monitor where the window opened, and the settings you
choose in that window affect only that monitor.
To control how the computer arranges multiple monitors, click the
Arrange button.
Follow the instructions in the Arrange window to adjust the settings. Your
new settings take effect immediately.
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