Mail app
The inbox names and content jitters (flashes in and out) when the mail app is open. Not always but a lot of the time. Can I refresh the app or remove and re-instate?
Thanks
MacBook Air 13″, macOS 10.13
Start with this...
Safe Boot, (holding Shift key down at startup), does the problem occur in Safe Mode? Could take 10 minutes or more.
Safe mode attempts to repair Disks & clears lots of caches & loads safe Drivers, & prevents loading of 3rd party extensions, so if Safe Mode works try again in regular boot.