Multi cursor not working anymore in Atom?

Here is how to fix the issue. The fix might reset other preset or settings in Atom, so please be aware of that.

First, bring up the console in Atom by clicking:

PC: (Ctrl + Shift + I)
MacOS: (Alt + Cmd + I on)

and then type in:

atom.config.set('core.editor.multiCursorOnClick', true);