# Uses of Package
com.google.gwt.event.dom.client

- Packages that use com.google.gwt.event.dom.client
  Package | Description
  --- | ---
  com.google.gwt.canvas.client | Classes for HTML Canvas 2D support.
  com.google.gwt.event.dom.client | Types related to DOM events.
  com.google.gwt.i18n.client | Internationalization support for GWT applications.
  com.google.gwt.media.client | Widgets for HTML Audio and Video support.
  com.google.gwt.touch.client |
  com.google.gwt.user.client | Fundamental user-interface classes used in client-side GWT code.
  com.google.gwt.user.client.ui | Widgets, Panels, and other user-interface classes.
  com.google.gwt.user.datepicker.client | The date picker widget and associated types.
  com.google.gwt.widget.client | Modern widgets, usually backed by Cells.

- Classes in com.google.gwt.event.dom.client used by com.google.gwt.canvas.client
  Class and Description
  HasAllDragAndDropHandlers This is a convenience interface that includes all drag and drop handlers defined by the core GWT system.
  HasAllFocusHandlers This is a convenience interface that includes all focus handlers defined by the core GWT system.
  HasAllGestureHandlers This is a convenience interface that includes all gesture handlers defined by the core GWT system.
  HasAllKeyHandlers Convenience interface used to implement all key handlers at once.
  HasAllMouseHandlers This is a convenience interface that includes all mouse handlers defined by the core GWT system.
  HasAllTouchHandlers This is a convenience interface that includes all touch handlers defined by the core GWT system.
  HasBlurHandlers A widget that implements this interface provides registration for `BlurHandler` instances.
  HasClickHandlers A widget that implements this interface provides registration for `ClickHandler` instances.
  HasDoubleClickHandlers A widget that implements this interface provides registration for `DoubleClickHandler` instances.
  HasDragEndHandlers A widget that implements this interface provides registration for `DragEndHandler` instances.
  HasDragEnterHandlers A widget that implements this interface provides registration for `DragEnterHandler` instances.
  HasDragHandlers A widget that implements this interface provides registration for `DragHandler` instances.
  HasDragLeaveHandlers A widget that implements this interface provides registration for `DragLeaveHandler` instances.
  HasDragOverHandlers A widget that implements this interface provides registration for `DragOverHandler` instances.
  HasDragStartHandlers A widget that implements this interface provides registration for `DragStartHandler` instances.
  HasDropHandlers A widget that implements this interface provides registration for `DropHandler` instances.
  HasFocusHandlers A widget that implements this interface provides registration for `FocusHandler` instances.
  HasGestureChangeHandlers A widget that implements this interface provides registration for `GestureChangeHandler` instances.
  HasGestureEndHandlers A widget that implements this interface provides registration for `GestureEndHandler` instances.
  HasGestureStartHandlers A widget that implements this interface provides registration for `GestureStartHandler` instances.
  HasKeyDownHandlers A widget that implements this interface provides registration for `KeyDownHandler` instances.
  HasKeyPressHandlers A widget that implements this interface provides registration for `KeyPressHandler` instances.
  HasKeyUpHandlers A widget that implements this interface provides registration for `KeyUpHandler` instances.
  HasMouseDownHandlers A widget that implements this interface provides registration for `MouseDownHandler` instances.
  HasMouseMoveHandlers A widget that implements this interface provides registration for `MouseMoveHandler` instances.
  HasMouseOutHandlers A widget that implements this interface provides registration for `MouseOutHandler` instances.
  HasMouseOverHandlers A widget that implements this interface provides registration for `MouseOverHandler` instances.
  HasMouseUpHandlers A widget that implements this interface provides registration for `MouseUpHandler` instances.
  HasMouseWheelHandlers A widget that implements this interface provides registration for `MouseWheelHandler` instances.
  HasTouchCancelHandlers A widget that implements this interface provides registration for `TouchCancelHandler` instances.
  HasTouchEndHandlers A widget that implements this interface provides registration for `TouchEndHandler` instances.
  HasTouchMoveHandlers A widget that implements this interface provides registration for `TouchMoveHandler` instances.
  HasTouchStartHandlers A widget that implements this interface provides registration for `TouchStartHandler` instances.

- Classes in com.google.gwt.event.dom.client used by com.google.gwt.event.dom.client
  Class and Description
  BlurEvent Represents a native blur event.
  BlurHandler Handler interface for `BlurEvent` events.
  CanPlayThroughEvent Represents a native media can play through event.
  CanPlayThroughHandler Handler interface for `CanPlayThroughEvent` events.
  ChangeEvent Represents a native change event.
  ChangeHandler Handler for `ChangeEvent` events.
  ClickEvent Represents a native click event.
  ClickHandler Handler for `ClickEvent` events.
  ContextMenuEvent Represents a native context menu event.
  ContextMenuHandler Handler for `ContextMenuEvent` events.
  DomEvent `DomEvent` is a subclass of `GwtEvent` that provides events that underlying native browser event object as well as a subclass of `DomEvent.Type` that understands GWT event bits used by sinkEvents().
  DomEvent.Type Type class used by dom event subclasses.
  DoubleClickEvent Represents a native double click event.
  DoubleClickHandler Handler interface for `DoubleClickEvent` events.
  DragDropEventBase Base class for drag and drop events.
  DragDropEventBase.DragSupportDetector Detector for browser support of drag events.
  DragEndEvent Represents a native drag end event.
  DragEndHandler Handler interface for `DragEndEvent` events.
  DragEnterEvent Represents a native drag enter event.
  DragEnterHandler Handler interface for `DragEnterEvent` events.
  DragEvent Represents a native drag event.
  DragHandler Handler interface for `DragEvent` events.
  DragLeaveEvent Represents a native drag leave event.
  DragLeaveHandler Handler interface for `DragLeaveEvent` events.
  DragOverEvent Represents a native drag over event.
  DragOverHandler Handler interface for `DragOverEvent` events.
  DragStartEvent Represents a native drag start event.
  DragStartHandler Handler interface for `DragStartEvent` events.
  DropEvent Represents a native drop event.
  DropHandler Handler interface for `DropEvent` events.
  EndedEvent Represents a native media ended event.
  EndedHandler Handler interface for `EndedEvent` events.
  ErrorEvent Represents a native error event.
  ErrorHandler Handler interface for `ErrorEvent` events.
  FocusEvent Represents a native focus event.
  FocusHandler Handler interface for `FocusEvent` events.
  GestureChangeEvent Represents a native gesture change event.
  GestureChangeHandler Handler interface for `GestureChangeEvent` events.
  GestureEndEvent Represents a native gesture end event.
  GestureEndHandler Handler interface for `GestureEndEvent` events.
  GestureStartEvent Represents a native gesture start event.
  GestureStartHandler Handler interface for `GestureStartEvent` events.
  HasAllFocusHandlers This is a convenience interface that includes all focus handlers defined by the core GWT system.
  HasAllKeyHandlers Convenience interface used to implement all key handlers at once.
  HasAllMouseHandlers This is a convenience interface that includes all mouse handlers defined by the core GWT system.
  HasAllTouchHandlers This is a convenience interface that includes all touch handlers defined by the core GWT system.
  HasBlurHandlers A widget that implements this interface provides registration for `BlurHandler` instances.
  HasCanPlayThroughHandlers A widget that implements this interface provides registration for `CanPlayThroughHandler` instances.
  HasDragEndHandlers A widget that implements this interface provides registration for `DragEndHandler` instances.
  HasDragEnterHandlers A widget that implements this interface provides registration for `DragEnterHandler` instances.
  HasDragHandlers A widget that implements this interface provides registration for `DragHandler` instances.
  HasDragLeaveHandlers A widget that implements this interface provides registration for `DragLeaveHandler` instances.
  HasDragOverHandlers A widget that implements this interface provides registration for `DragOverHandler` instances.
  HasDragStartHandlers A widget that implements this interface provides registration for `DragStartHandler` instances.
  HasDropHandlers A widget that implements this interface provides registration for `DropHandler` instances.
  HasEndedHandlers A widget that implements this interface provides registration for `EndedHandler` instances.
  HasFocusHandlers A widget that implements this interface provides registration for `FocusHandler` instances.
  HasGestureChangeHandlers A widget that implements this interface provides registration for `GestureChangeHandler` instances.
  HasGestureEndHandlers A widget that implements this interface provides registration for `GestureEndHandler` instances.
  HasGestureStartHandlers A widget that implements this interface provides registration for `GestureStartHandler` instances.
  HasKeyDownHandlers A widget that implements this interface provides registration for `KeyDownHandler` instances.
  HasKeyPressHandlers A widget that implements this interface provides registration for `KeyPressHandler` instances.
  HasKeyUpHandlers A widget that implements this interface provides registration for `KeyUpHandler` instances.
  HasMouseDownHandlers A widget that implements this interface provides registration for `MouseDownHandler` instances.
  HasMouseMoveHandlers A widget that implements this interface provides registration for `MouseMoveHandler` instances.
  HasMouseOutHandlers A widget that implements this interface provides registration for `MouseOutHandler` instances.
  HasMouseOverHandlers A widget that implements this interface provides registration for `MouseOverHandler` instances.
  HasMouseUpHandlers A widget that implements this interface provides registration for `MouseUpHandler` instances.
  HasMouseWheelHandlers A widget that implements this interface provides registration for `MouseWheelHandler` instances.
  HasNativeEvent An object that implements this interface has a native event associated with it.
  HasProgressHandlers A widget that implements this interface provides registration for `ProgressHandler` instances.
  HasTouchCancelHandlers A widget that implements this interface provides registration for `TouchCancelHandler` instances.
  HasTouchEndHandlers A widget that implements this interface provides registration for `TouchEndHandler` instances.
  HasTouchMoveHandlers A widget that implements this interface provides registration for `TouchMoveHandler` instances.
  HasTouchStartHandlers A widget that implements this interface provides registration for `TouchStartHandler` instances.
  HumanInputEvent Abstract class representing position events such as mouse or touch events.
  KeyCodeEvent Key up and key down are both events based upon a given key code.
  KeyDownEvent Represents a native key down event.
  KeyDownHandler Handler interface for `KeyDownEvent` events.
  KeyEvent Base class for Key events.
  KeyPressEvent Represents a native key press event.
  KeyPressHandler Handler interface for `KeyPressEvent` events.
  KeyUpEvent Represents a native key up event.
  KeyUpHandler Handler interface for `KeyUpEvent` events.
  LoadEvent Represents a native load event.
  LoadHandler Handler interface for `LoadEvent` events.
  LoseCaptureEvent Represents a native lose capture event.
  LoseCaptureHandler Handler interface for `LoseCaptureEvent` events.
  MouseDownEvent Represents a native mouse down event.
  MouseDownHandler Handler interface for `MouseDownEvent` events.
  MouseEvent Abstract class representing mouse events.
  MouseMoveEvent Represents a native mouse move event.
  MouseMoveHandler Handler interface for `MouseMoveEvent` events.
  MouseOutEvent Represents a native mouse out event.
  MouseOutHandler Handler interface for `MouseOutEvent` events.
  MouseOverEvent Represents a native mouse over event.
  MouseOverHandler Handler interface for `MouseOverEvent` events.
  MouseUpEvent Represents a native mouse up event.
  MouseUpHandler Handler interface for `MouseUpEvent` events.
  MouseWheelEvent Represents a native mouse wheel event.
  MouseWheelHandler Handler interface for `MouseWheelEvent` events.
  ProgressEvent Represents a native media progress event.
  ProgressHandler Handler interface for `ProgressEvent` events.
  ScrollEvent Represents a native scroll event.
  ScrollHandler Handler interface for `ScrollEvent` events.
  TouchCancelEvent Represents a native touch start event.
  TouchCancelHandler Handler interface for `TouchCancelEvent` events.
  TouchEndEvent Represents a native touch end event.
  TouchEndHandler Handler interface for `TouchEndEvent` events.
  TouchEvent Abstract class representing touch events.
  TouchMoveEvent Represents a native touch move event.
  TouchMoveHandler Handler interface for `TouchMoveEvent` events.
  TouchStartEvent Represents a native touch start event.
  TouchStartHandler Handler interface for `TouchStartEvent` events.

- Classes in com.google.gwt.event.dom.client used by com.google.gwt.i18n.client
  Class and Description
  HasKeyUpHandlers A widget that implements this interface provides registration for `KeyUpHandler` instances.
  KeyUpEvent Represents a native key up event.
  KeyUpHandler Handler interface for `KeyUpEvent` events.

- Classes in com.google.gwt.event.dom.client used by com.google.gwt.media.client
  Class and Description
  CanPlayThroughHandler Handler interface for `CanPlayThroughEvent` events.
  EndedHandler Handler interface for `EndedEvent` events.
  HasAllDragAndDropHandlers This is a convenience interface that includes all drag and drop handlers defined by the core GWT system.
  HasAllFocusHandlers This is a convenience interface that includes all focus handlers defined by the core GWT system.
  HasAllGestureHandlers This is a convenience interface that includes all gesture handlers defined by the core GWT system.
  HasAllKeyHandlers Convenience interface used to implement all key handlers at once.
  HasAllMediaHandlers This is a convenience interface that includes all media handlers defined by the core GWT system.
  HasAllMouseHandlers This is a convenience interface that includes all mouse handlers defined by the core GWT system.
  HasAllTouchHandlers This is a convenience interface that includes all touch handlers defined by the core GWT system.
  HasBlurHandlers A widget that implements this interface provides registration for `BlurHandler` instances.
  HasCanPlayThroughHandlers A widget that implements this interface provides registration for `CanPlayThroughHandler` instances.
  HasClickHandlers A widget that implements this interface provides registration for `ClickHandler` instances.
  HasDoubleClickHandlers A widget that implements this interface provides registration for `DoubleClickHandler` instances.
  HasDragEndHandlers A widget that implements this interface provides registration for `DragEndHandler` instances.
  HasDragEnterHandlers A widget that implements this interface provides registration for `DragEnterHandler` instances.
  HasDragHandlers A widget that implements this interface provides registration for `DragHandler` instances.
  HasDragLeaveHandlers A widget that implements this interface provides registration for `DragLeaveHandler` instances.
  HasDragOverHandlers A widget that implements this interface provides registration for `DragOverHandler` instances.
  HasDragStartHandlers A widget that implements this interface provides registration for `DragStartHandler` instances.
  HasDropHandlers A widget that implements this interface provides registration for `DropHandler` instances.
  HasEndedHandlers A widget that implements this interface provides registration for `EndedHandler` instances.
  HasFocusHandlers A widget that implements this interface provides registration for `FocusHandler` instances.
  HasGestureChangeHandlers A widget that implements this interface provides registration for `GestureChangeHandler` instances.
  HasGestureEndHandlers A widget that implements this interface provides registration for `GestureEndHandler` instances.
  HasGestureStartHandlers A widget that implements this interface provides registration for `GestureStartHandler` instances.
  HasKeyDownHandlers A widget that implements this interface provides registration for `KeyDownHandler` instances.
  HasKeyPressHandlers A widget that implements this interface provides registration for `KeyPressHandler` instances.
  HasKeyUpHandlers A widget that implements this interface provides registration for `KeyUpHandler` instances.
  HasMouseDownHandlers A widget that implements this interface provides registration for `MouseDownHandler` instances.
  HasMouseMoveHandlers A widget that implements this interface provides registration for `MouseMoveHandler` instances.
  HasMouseOutHandlers A widget that implements this interface provides registration for `MouseOutHandler` instances.
  HasMouseOverHandlers A widget that implements this interface provides registration for `MouseOverHandler` instances.
  HasMouseUpHandlers A widget that implements this interface provides registration for `MouseUpHandler` instances.
  HasMouseWheelHandlers A widget that implements this interface provides registration for `MouseWheelHandler` instances.
  HasProgressHandlers A widget that implements this interface provides registration for `ProgressHandler` instances.
  HasTouchCancelHandlers A widget that implements this interface provides registration for `TouchCancelHandler` instances.
  HasTouchEndHandlers A widget that implements this interface provides registration for `TouchEndHandler` instances.
  HasTouchMoveHandlers A widget that implements this interface provides registration for `TouchMoveHandler` instances.
  HasTouchStartHandlers A widget that implements this interface provides registration for `TouchStartHandler` instances.
  ProgressHandler Handler interface for `ProgressEvent` events.

- Classes in com.google.gwt.event.dom.client used by com.google.gwt.touch.client
  Class and Description
  TouchEvent Abstract class representing touch events.

- Classes in com.google.gwt.event.dom.client used by com.google.gwt.user.client
  Class and Description
  HasNativeEvent An object that implements this interface has a native event associated with it.

- Classes in com.google.gwt.event.dom.client used by com.google.gwt.user.client.ui
  Class and Description
  BlurEvent Represents a native blur event.
  BlurHandler Handler interface for `BlurEvent` events.
  ChangeEvent Represents a native change event.
  ChangeHandler Handler for `ChangeEvent` events.
  ClickEvent Represents a native click event.
  ClickHandler Handler for `ClickEvent` events.
  DomEvent.Type Type class used by dom event subclasses.
  DoubleClickHandler Handler interface for `DoubleClickEvent` events.
  DragEndHandler Handler interface for `DragEndEvent` events.
  DragEnterHandler Handler interface for `DragEnterEvent` events.
  DragHandler Handler interface for `DragEvent` events.
  DragLeaveHandler Handler interface for `DragLeaveEvent` events.
  DragOverHandler Handler interface for `DragOverEvent` events.
  DragStartHandler Handler interface for `DragStartEvent` events.
  DropHandler Handler interface for `DropEvent` events.
  ErrorEvent Represents a native error event.
  ErrorHandler Handler interface for `ErrorEvent` events.
  FocusEvent Represents a native focus event.
  FocusHandler Handler interface for `FocusEvent` events.
  GestureChangeHandler Handler interface for `GestureChangeEvent` events.
  GestureEndHandler Handler interface for `GestureEndEvent` events.
  GestureStartHandler Handler interface for `GestureStartEvent` events.
  HasAllDragAndDropHandlers This is a convenience interface that includes all drag and drop handlers defined by the core GWT system.
  HasAllFocusHandlers This is a convenience interface that includes all focus handlers defined by the core GWT system.
  HasAllGestureHandlers This is a convenience interface that includes all gesture handlers defined by the core GWT system.
  HasAllKeyHandlers Convenience interface used to implement all key handlers at once.
  HasAllMouseHandlers This is a convenience interface that includes all mouse handlers defined by the core GWT system.
  HasAllTouchHandlers This is a convenience interface that includes all touch handlers defined by the core GWT system.
  HasBlurHandlers A widget that implements this interface provides registration for `BlurHandler` instances.
  HasChangeHandlers A widget that implements this interface provides registration for `ChangeHandler` instances.
  HasClickHandlers A widget that implements this interface provides registration for `ClickHandler` instances.
  HasDoubleClickHandlers A widget that implements this interface provides registration for `DoubleClickHandler` instances.
  HasDragEndHandlers A widget that implements this interface provides registration for `DragEndHandler` instances.
  HasDragEnterHandlers A widget that implements this interface provides registration for `DragEnterHandler` instances.
  HasDragHandlers A widget that implements this interface provides registration for `DragHandler` instances.
  HasDragLeaveHandlers A widget that implements this interface provides registration for `DragLeaveHandler` instances.
  HasDragOverHandlers A widget that implements this interface provides registration for `DragOverHandler` instances.
  HasDragStartHandlers A widget that implements this interface provides registration for `DragStartHandler` instances.
  HasDropHandlers A widget that implements this interface provides registration for `DropHandler` instances.
  HasErrorHandlers A widget that implements this interface provides registration for `ErrorHandler` instances.
  HasFocusHandlers A widget that implements this interface provides registration for `FocusHandler` instances.
  HasGestureChangeHandlers A widget that implements this interface provides registration for `GestureChangeHandler` instances.
  HasGestureEndHandlers A widget that implements this interface provides registration for `GestureEndHandler` instances.
  HasGestureStartHandlers A widget that implements this interface provides registration for `GestureStartHandler` instances.
  HasKeyDownHandlers A widget that implements this interface provides registration for `KeyDownHandler` instances.
  HasKeyPressHandlers A widget that implements this interface provides registration for `KeyPressHandler` instances.
  HasKeyUpHandlers A widget that implements this interface provides registration for `KeyUpHandler` instances.
  HasLoadHandlers A widget that implements this interface provides registration for `LoadHandler` instances.
  HasMouseDownHandlers A widget that implements this interface provides registration for `MouseDownHandler` instances.
  HasMouseMoveHandlers A widget that implements this interface provides registration for `MouseMoveHandler` instances.
  HasMouseOutHandlers A widget that implements this interface provides registration for `MouseOutHandler` instances.
  HasMouseOverHandlers A widget that implements this interface provides registration for `MouseOverHandler` instances.
  HasMouseUpHandlers A widget that implements this interface provides registration for `MouseUpHandler` instances.
  HasMouseWheelHandlers A widget that implements this interface provides registration for `MouseWheelHandler` instances.
  HasScrollHandlers A widget that implements this interface provides registration for `ScrollHandler` instances.
  HasTouchCancelHandlers A widget that implements this interface provides registration for `TouchCancelHandler` instances.
  HasTouchEndHandlers A widget that implements this interface provides registration for `TouchEndHandler` instances.
  HasTouchMoveHandlers A widget that implements this interface provides registration for `TouchMoveHandler` instances.
  HasTouchStartHandlers A widget that implements this interface provides registration for `TouchStartHandler` instances.
  KeyDownEvent Represents a native key down event.
  KeyDownHandler Handler interface for `KeyDownEvent` events.
  KeyPressEvent Represents a native key press event.
  KeyPressHandler Handler interface for `KeyPressEvent` events.
  KeyUpEvent Represents a native key up event.
  KeyUpHandler Handler interface for `KeyUpEvent` events.
  LoadEvent Represents a native load event.
  LoadHandler Handler interface for `LoadEvent` events.
  MouseDownEvent Represents a native mouse down event.
  MouseDownHandler Handler interface for `MouseDownEvent` events.
  MouseMoveEvent Represents a native mouse move event.
  MouseMoveHandler Handler interface for `MouseMoveEvent` events.
  MouseOutEvent Represents a native mouse out event.
  MouseOutHandler Handler interface for `MouseOutEvent` events.
  MouseOverEvent Represents a native mouse over event.
  MouseOverHandler Handler interface for `MouseOverEvent` events.
  MouseUpEvent Represents a native mouse up event.
  MouseUpHandler Handler interface for `MouseUpEvent` events.
  MouseWheelEvent Represents a native mouse wheel event.
  MouseWheelHandler Handler interface for `MouseWheelEvent` events.
  ScrollEvent Represents a native scroll event.
  ScrollHandler Handler interface for `ScrollEvent` events.
  TouchCancelHandler Handler interface for `TouchCancelEvent` events.
  TouchEndHandler Handler interface for `TouchEndEvent` events.
  TouchMoveHandler Handler interface for `TouchMoveEvent` events.
  TouchStartHandler Handler interface for `TouchStartEvent` events.

- Classes in com.google.gwt.event.dom.client used by com.google.gwt.user.datepicker.client
  Class and Description
  HasAllDragAndDropHandlers This is a convenience interface that includes all drag and drop handlers defined by the core GWT system.
  HasClickHandlers A widget that implements this interface provides registration for `ClickHandler` instances.
  HasDoubleClickHandlers A widget that implements this interface provides registration for `DoubleClickHandler` instances.
  HasDragEndHandlers A widget that implements this interface provides registration for `DragEndHandler` instances.
  HasDragEnterHandlers A widget that implements this interface provides registration for `DragEnterHandler` instances.
  HasDragHandlers A widget that implements this interface provides registration for `DragHandler` instances.
  HasDragLeaveHandlers A widget that implements this interface provides registration for `DragLeaveHandler` instances.
  HasDragOverHandlers A widget that implements this interface provides registration for `DragOverHandler` instances.
  HasDragStartHandlers A widget that implements this interface provides registration for `DragStartHandler` instances.
  HasDropHandlers A widget that implements this interface provides registration for `DropHandler` instances.

- Classes in com.google.gwt.event.dom.client used by com.google.gwt.widget.client
  Class and Description
  BlurHandler Handler interface for `BlurEvent` events.
  ClickHandler Handler for `ClickEvent` events.
  FocusHandler Handler interface for `FocusEvent` events.
  HasAllFocusHandlers This is a convenience interface that includes all focus handlers defined by the core GWT system.
  HasAllKeyHandlers Convenience interface used to implement all key handlers at once.
  HasBlurHandlers A widget that implements this interface provides registration for `BlurHandler` instances.
  HasClickHandlers A widget that implements this interface provides registration for `ClickHandler` instances.
  HasFocusHandlers A widget that implements this interface provides registration for `FocusHandler` instances.
  HasKeyDownHandlers A widget that implements this interface provides registration for `KeyDownHandler` instances.
  HasKeyPressHandlers A widget that implements this interface provides registration for `KeyPressHandler` instances.
  HasKeyUpHandlers A widget that implements this interface provides registration for `KeyUpHandler` instances.
  HasMouseDownHandlers A widget that implements this interface provides registration for `MouseDownHandler` instances.
  HasMouseOutHandlers A widget that implements this interface provides registration for `MouseOutHandler` instances.
  HasMouseOverHandlers A widget that implements this interface provides registration for `MouseOverHandler` instances.
  HasMouseUpHandlers A widget that implements this interface provides registration for `MouseUpHandler` instances.
  KeyDownHandler Handler interface for `KeyDownEvent` events.
  KeyPressHandler Handler interface for `KeyPressEvent` events.
  KeyUpHandler Handler interface for `KeyUpEvent` events.
  MouseDownHandler Handler interface for `MouseDownEvent` events.
  MouseOutHandler Handler interface for `MouseOutEvent` events.
  MouseOverHandler Handler interface for `MouseOverEvent` events.
  MouseUpHandler Handler interface for `MouseUpEvent` events.