Ask Proxima C350 Reference Manual page 16

For Macintosh: Image fuzzy or cropped
A
Only my laptop's background appears, not the
Desktop icons
Set your computer's display resolution to
the native resolution of the projector
A
(Apple menu>System
Preferences>Displays, choose 1024x768)
Disable "Extend my Windows Desktop" in
Control Panel>Display>Settings>Display 2
(location varies by operating system)
Uncheck this
option, then
click Apply
15
Image clear and not cropped
A
Background and Desktop projected