How do I get a MacBook Air to extend display on 2008 iMac?
From the Mac Book Air I have used Display port to VGA and from the VGA to the iMac I have used VGA to mini-DVI connector. When I go to Display, arrangement, both monitors show a 2nd screen, however in the arrangement tab they both see the larger rectangle as their own display, and so it will not extend or mirror the view. Do I have the wrong connectors? If so, I'm not sure which connector to get for the 2008 iMac.
MacBook Air, macOS Sierra (10.12.6)