Apple Studio Display 21: Do Not Daisy Chain Multiple Displays Together
If you daisy chain multiple Apple Studio Display 21-inch displays together, the Power Macintosh G3 (Blue and White) may restart itself approximately 3-5 seconds after you shut down.
If this occurs, reconnect the additional displays directly to your Power Macintosh G3 (Blue and White).
Alternatively, you can use a USB hub. Although the Apple Studio Display 21"-inch is a USB hub, the four ports on the side should be used for connecting other USB devices.
The viewable image size of the Apple Studio Display 21-inch is 19.8 inches.