anchor.diff:    MOUSEWHEEL,
   
     /// The mouse has been moved to point at this widget. A widget that is
  -  /// interested in receiving Drag And Drop data must return 1 to receive
  +  /// interested in receiving Drag And Drop data must return true to receive
     /// [DND_DRAG], [DND_LEAVE] and [DND_RELEASE] events.
     DND_ENTER,
   
  
positive.code: 
    /// The mouse has moved without any mouse buttons held down. This event is
    /// sent to the [belowmouse] widget. In order to receive [MOVE] events, the
    /// widget must return non-zero when handling [ENTER].
    MOVE,
  
    /// If the [focus] widget is null or ignores a [KEYBOARD] event then FLTK
    /// tries sending this event to every widget it can, until one of them returns
    /// non-zero.
    ///
    /// SHORTCUT is first sent to the [belowmouse] widget, then its parents and
    /// siblings, and eventually to every widget in the window, trying to find an
    /// object that returns non-zero. FLTK tries really hard to not to ignore any
    /// keystrokes!
    ///
    /// You can also make global shortcuts by using [addHandler]. A global
  
negative.code:   DND_LEAVE,
  
    /// The user has released the mouse button dropping data into the widget. If
    /// the widget returns true, it will receive the data in the immediately
    /// following [PASTE] event.
    DND_RELEASE,
  
  