Oracle Forms fully supports both the Microsoft Windows MDI (Multiple Document Interface) and SDI (Single Document Interface) systems of window management.
MDI applications display a default parent window, called the application window. All other windows in the application are either document windows or dialog windows.
Document windows always are displayed within the MDI application window frame. If the end user resizes the MDI window so it is smaller than a document window, the document window is clipped. End users can maximize a document window so that it occupies the entire content area of the application window. Dialog windows are free-floating, and the end user can move them outside the application window if they are defined as movable. If the end user resizes the MDI window to make it smaller than a dialog window, the dialog window is not clipped.
The MDI application window is created by the window manager at runtime, and does not appear in a form's List of windows. However, you can use the SET_WINDOW_PROPERTY Built-in to resize, minimize, and maximize the MDI window programmatically.
Although MDI is the default system of window management during Forms Runtime, Oracle Forms also provides support for an SDI root window on Microsoft Windows.
You can set the system of window management to SDI by specifying the USESDI command line option. When SDI is enabled, calls to the FORMS_MDI_WINDOW constant returns NULL for the MDI window handle. There is no multiple interface root window, MDI toolbars exist in parent windows, and MDI menus are attached to each window.