Clicking the red ✕ button doesn't quit the app — it's still running in the background
You close a window by clicking the red button and think you've closed the app. But it's still running — there's a dot under its Dock icon. It's using memory, possibly running processes, and showing up in ⌘+Tab. On Windows, closing the window means closing the program. Not on Mac.
Why does this happen?
macOS separates closing a window from quitting an application by design. Apps are expected to remain running even with no windows open, so you can reopen them instantly. It's a different app lifecycle model from Windows — not wrong, just different, and very confusing for switchers.
How to fix it
To actually quit an app: press ⌘+Q, or right-click its Dock icon → Quit, or use the app menu → Quit.
To quit unused apps automatically: apps like Quitter can quit apps after they've been unused for a set time.
Most apps are fine left running — macOS manages memory well. But if you want a clean slate, ⌘+Q is your friend.
Discussion
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