Size this window to its preferred size and make it
displayable, and override the base class to populate the menu
bar if the menus have not already been populated.
This is the 3rd version of SwingWorker (also known as
SwingWorker 3), an abstract class that you subclass to
perform GUI-related work in a dedicated thread.
The FileFilter that determines what files are displayed by
the Open dialog and the Save As dialog
The initial default is null, which causes no FileFilter to be
applied, which results in all files being displayed.
Get the name of this object, which in this base class is
either the name of the file that has been associated with this
object, or the string "Unnamed" is none.
If the contents of this dialog implements the CloseListener
interface, then notify it that the window has closed, unless
notification has already been done (it is guaranteed to be done
only once).