Click X in the upper right corner of the window while pressing the SHIFT key. Alternatively, you can close all in the following ways:
•Press ALT + SHIFT + F4.
•Press ALT + SHIFT + X.
•Select Close from the File menu while pressing the SHIFT key.
•Add the Close All button on the Toolbar, and click that button.
•Click the Tray Icon and select Close All from the menu.