Focus identifies the currently active or primary window. The current focus can be one of the multiple windows. Only one window has focus at a time. The window with the current focus is identified with a red border and a blue title bar at the top of the window. All other displayed windows will have a grey title bar when they are not the current focus. The displayed function key labels reflect the currently focused window.
To change the focus automatically, press DISP without pressing the SHIFT key. After you have changed the focus, you can then perform the functions that are allowed for the currently active window.