Subclasses may override this.
Subclasses may override this. If this method returns true, the window may be closed,
otherwise a closure is aborted. By default this always returns true.
Subclasses may override this.
Subclasses may override this. The tuple is (horizontal, vertical, padding) position.
By default it centers the window, i.e. (0.5f, 0.5f, 20).
Subclasses may override this.
Subclasses may override this.