Modal window

In user interface design, a modal window, or modal for short, is a graphical control element subordinate to an application's main window. A modal window creates a mode that disables user interaction with the main window but keeps it visible, with the modal window as a child window in front of it. In regular practice a user has to interact with the modal window in order to be returned to the parent window. This avoids interrupting the workflow on the main window. Modal windows are sometimes called heavy windows or modal dialogs because they often display a dialog box. User interfaces typically use modal windows to command user awareness and to display emergency states, though interaction designers argue they are ineffective for that use. Modal windows are prone to mode errors. On the Web, modal windows are often used to show an image in detail, (for example as implemented by the Lightbox library,) or for hover ads. The opposite of modal is modeless. Modeless windows don't block the main window, so the user can switch their focus between them, treating them as palette windows.