Maximizing (not fulll screen) safari window in Bug Sur not working (Option Click Plus)
I finally got it to work in Safari. Move the mouse cursor all the way to the corner of the Safari window. The cursor should change to and angled arrow with two ends. If you double click while the cursor is a double ended arrow the screen will expand to one side of the screen depending on which side of the window you are clicking on (left or right). Hold the option key while double clicking the arrow to expand out both sides.