TopBarMenu -- Overview
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 Class Function

 TopBar()        Create a new TopBarMenu object
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 Exported Instance Variables

 cargo           User-definable variable
 colorSpec       Indicates colors used by the top bar menu's display() method
 current         Numeric value indicating which item is selected
 itemCount       Numeric value indicating total number of items in TopBarMenu
 left            Numeric value indicating the top bar menu's leftmost column
 right           Numeric value indicating the top bar menu's rightmost column
 row             Numeric value indicating row where the top bar menu appears
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 Exported Methods

 addItem()       Appends a new item to a top bar menu
 delItem()       Removes an item from a top bar menu
 display()       Shows a top bar menu and its items on the screen
 getFirst()      Determines position of the first selectable item in a menu
 getItem()       Accesses a MenuItem object after it has been added to a menu
 getLast()       Determines position of the last selectable item in a menu
 getNext()       Determines position of the next selectable item in a menu
 getPrev()       Determines position of previous selectable item in a menu
 getAccel()      Determines if a key press is interpreted as a user request
 hitTest()       Indicates position of mouse cursor relative to menu
 insItem()       Inserts a new item in a top bar menu
 select()        Changes the selected item
 setItem()       Replaces a MenuItem object after it has been added to a menu