error in public function admin_editor_styles ( $mce_css )

Hi, in this function you only return the $mce_css in the if statement. This killed all backend css from other plugins and themes.
Here is how I think it should be:

/**
	 * Load Editor Stylesheets.
	 * @access  public
	 * @since   1.0.0
	 */
	public function admin_editor_styles (  $mce_css ) {

		if ( get_option('fp_load_foundation_icons_checkbox', true) == true ) {
			$mce_css .= ', ' . plugins_url( 'assets/foundation/foundation-icons/foundation-icons.css',  dirname(__FILE__));
		}
		return $mce_css;
		
	} // End admin_editor_styles ()

Regards
Lennart