The Full-Screen Frustration
macOS has a very specific way of handling window management. If you take a window (like a Safari browser or a Pages document) and move it to a different monitor, or if you unplug your laptop from an external display, the operating system attempts to automatically resize the window to fit the new screen real estate. While sometimes helpful, this can ruin a carefully arranged workspace. Even more frustrating is the green “maximize” button in the top-left corner of a window. By default, clicking this button doesn’t just maximize the window; it throws the application into a dedicated, isolated Full Screen “Space,” completely obscuring the menu bar and the Dock, and hiding all your other open apps.
Modifying Window Management Preferences
To retain control over your window dimensions and stop macOS from automatically resizing windows into dedicated Full Screen spaces when you click the maximize button, you need to adjust a hidden setting.
You can change the behavior of the green traffic light button simply by holding down a modifier key. When you hover your mouse over the green button, hold down the Option (⌥) key on your keyboard. You will see the two little expanding arrows inside the button change to a plus (+) symbol. If you click the button while holding Option, the window will simply expand to fill the available screen space without forcing you into a separate Full Screen space. If you want this to be the permanent behavior without having to press Option every time, you will need a third-party window management utility like Magnet or Rectangle, as Apple does not provide a native toggle switch in System Settings to reverse this default action.