code: @Override
  	public boolean removeActor (final Actor actor, final boolean unfocus) {
  		if (getActor().getChildren().contains(actor, true)) {
  			// Stage input focus causes problems, as touchUp is called in Draggable. Reproducing input unfocus after stage removed.
  			Stage stage = actor.getStage();
  			getActor().removeActor(actor, false); // Stage is cleared.
  			if (unfocus && stage != null) {
  				stage.unfocus(actor);
  			}
  			return true;
  		}
  		return false;
  	}
docs: Removes an actor from this group. If the actor will not be used again and has actions, they should be
  {@link Actor#clearActions() cleared} so the actions will be returned to their
  {@link Action#setPool(com.badlogic.gdx.utils.Pool) pool}, if any. This is not done automatically.
  <p>
  Note that the direct parent of {@link DragPane}'s children is the internal pane's group accessible through
  {@link #getGroup()} - and since this removal method is overridden and extended, pane's children should be deleted with
  {@code dragPane.removeActor(child, true)} rather than {@link Actor#remove()} method.
  @param unfocus if true, {@link Stage#unfocus(Actor)} is called.
  @param actor will be removed, if present in the internal {@link WidgetGroup}.
  @return true if the actor was removed from this group.