Do you want frameless windows on your Electron app? There's a framework even for that! No need to rebuild the wheel for every Electron app you develop. Framlr is a window frame boilerplate to be used on Electron apps with frameless windows.
Unlike other buttons, this button will not perform a action, because some apps shows a dialog before closing it, or move the app to system tray when clicked on close button; so its up to the app to handle the action of this button