Extend my display using Catalina
I updated my mac to Catalina. I can no longer Extend my display to a 2nd monitor. The "Arrangements" tab is no longer there in my display options. Any help on this?
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Try using extended desktop mode instead of mirror display mode. Mirror display also mirrors the display resolution. Extended desktop mode allows you to select the native resolution of the external display.
See if you still have this option >System Preferences>Displays
press the option key while you're in Displays— You'll get a Detect displays button (bottom right).
there is a checkbox "Show displays in menu bar". If you check it, you get a new icon in the menu bar that has "Detect Displays" as its first option.
Use external monitors with your Mac: https://support.apple.com/en-us/HT202351
Get help with video issues on external displays connected to your Mac - Apple Support
 https://support.apple.com/en-us/HT201177