I use a very specific workflow with the Messages app on the Mac:
- Read my messages
- Close the Messages window with CMD-W
- Messages app is still running
- When a new message comes in, CMD-Tab to the still-open Messages app
- Press CMD-0 to re-open the Messages window
After closing the Messages window, the app has always remained open and running in the Dock and app switcher.
In Mac OS 10.14 Mojave, I similarly close the Messages window. After closing the Messages window, the Messages app is still in the foreground, running, and shows the menu bar.
When I click to some other app, however, the Messages app then immediately seemingly Quits.
The dot disappears from the dock, and (this is the key issue) I can no longer CMD-Tab to the Messages app in the app switcher.
I'm forced to go click the dock icon with my mouse or otherwise re-open the app, which is inconvenient and annoying.
After the app has Quit, besides being "Quit", it seems to behave more-or-less exactly how it used to behave pre-Mojave. The Messages process is still running and visible in Activity Monitor. Notifications continue to arrive. The dock icon gets badged.
How do I prevent Messages from quitting when I close its window?
rdar://46142132 - Mojave Messages.app should not quit when I close its window
Engineering has determined that your bug report (46142132) is a duplicate of 42085189 and will be closed.