PushButton -- Overview
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 Class Function

 PushButton()    Create a new PushButton object
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 Exported Instance Variables

 bitmap          The bitmap file to display on the button
 bmpXOff         Indicates the horizontal offset where the bitmap is displayed
 bmpYOff         Indicates the vertical offset where the bitmap is displayed
 buffer          Logical value indicating the push button has been pushed
 caption         Character string describing the push button on the screen
 capXOff         Indicates the horizontal offset where caption is displayed
 capYOff         Indicates the vertical offset where caption is displayed
 cargo           User-definable variable
 col             Indicates screen column where push button is displayed
 colorSpec       Indicates colors used by the push button's display() method
 fBlock          Code block evaluated at each input focus change
 hasFocus        Logical value indicating the input focus
 message         Character string describing the push button
 row             Numeric value indicating row where push button is displayed
 sBlock          Code block evaluated at every state change
 sizeX           Size of the button in pixels on the X-coordinate
 sizeY           Size of the button in pixels on the Y-coordinate
 style           Indicates characters used by push button's display() method
 typeOut         Logical value false (.F.)
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 Exported Methods

 display()       Shows a push button on the screen
 hitTest()       Indicates position of mouse cursor relative to push button
 killFocus()     Takes input focus away from the PushButton object
 select()        Activates a push button
 setFocus()      Gives input focus to the PushButton object