Subclass of widgets which only accept child of type T.
Maanrifa Bacar Ali
Adds given item to the current widget.
Adds given item to the current widget at the given position.
Adds a list of items to the current widget.
Removes all items from the current widget and disposes them.
Removes given item from the current widget.
Removes all items from the current widget.
Removes the item from the current widget at the given position.