The dot icon on the dock stays despite I have closed the app

As the title clearly describes, the dot icon stays on dock for some apps such as VS Code, Terminal, Safari, and Finder despite I have closed the app. I am using Catalina 10.15.1. I have to manually right click those apps and select Quit in order to remove the dots on the dock.

Solution 1:

The presence of a dot below an app icon in Dock indicates that the app is still running.

Clicking on the red 🅧 traffic light button in the app window title bar, doesn't quit every macOS app. The default behavior of a macOS is to not quit upon clicking the button.

Some apps are programmed to quit upon clicking the red 🅧 traffic light button, but most keep running unless you explicitly quit them by running the App Name → Quit App Name command in the menu bar, or using the keyboard shortcut Command + Q, or right clicking on the app icon in the Dock and selecting Quit.