A->Visible = true; $this->B->Visible = false; $this->Main->render( $param->NewWriter ); } public function showBcallback( $sender, $param ) { $this->A->Visible = false; $this->B->Visible = true; $this->Main->render( $param->NewWriter ); } public function clicked( $sender, $param ) { $sender->Text = $sender->Text.' clicked'; } }