code: public void setController(AbstractFreeDrawingController controller) {
  		if (this.controller != null) {
  			this.controller.onDeactivate();
  		}
  		this.controller = controller;
  		if (controller != null) {
  			controller.setMaxBoundsDisplayed(isMaxBoundsDisplayed());
  			controller.onActivate();
  		} else {
  			onActivate();
  		}
  	}
docs: Set a new child draw controller. If there was a previous child controller, then it's <code>onDeactivate</code>
  method will be called first. Likewise on the new controller, the <code>onActivate</code> will be called.
  
  @param controller
  The new child draw controller. A controller usually masters drawing for one type of geometry. This
  parameter can also be <code>null</code>, when no child draw controller is required anymore. If this
  parameter is <code>null</code>, then this controller <code>onActivate</code> method is called.