-  Header -- Display/Edit  header.
    
-  Hist -- Displays a histogram image of 1 or 2 columns in a table
    
-  Image/Plot  -- Display image or plot table column values.
         The default image
         display device (POW or ds9) may be selected under the
         Edit->Preferences->Graphs menu item.  
    
-  Table  -- Display a table. (If the extension is an image, then
         numerical values of the image are displayed as a table).  
             All - displays all the columns in a table
             Select -  allows the user to select which columns to display.   
 By clicking each button, users are allowed to display and edit
    the FITS file.