Starting in version 20, all windows that you open are docked to the main window by default. To switch between them, just click the tab of the window that you want to view.
To close a window, click the X on its tab.
To undock a window, allowing you to view more than one Inform window at a time, click the tab and drag it outside the Inform window.
To dock the window again, right-click in the title bar, and then click Dock Window.