#Resize off screen window
The tip is from https://www.tekrevue.com/tip/resize-off-screen-window-in-mac-os-x/
Simply select your desired application to make it active by click on its icon in the Dock (you should see the application's name in the top-left corner of your OS X Menu Bar, next to the Apple logo). Then, also in the Menu Bar, click the word Window and then Zoom.