public function setIcon( $icon = null ) {
		if ( $this->iconName !== null ) {
			$this->icon->removeClasses( [ 'oo-ui-icon-' . $this->iconName ] );
		}
		if ( $icon !== null ) {
			$this->icon->addClasses( [ 'oo-ui-icon-' . $icon ] );
		}

		$this->iconName = $icon;
		$this->toggleClasses( [ 'oo-ui-iconElement' ], (bool)$this->iconName );
		$this->icon->toggleClasses( [ 'oo-ui-iconElement-noIcon' ], !$this->iconName );

		return $this;
	}