code: function _getBkgImageOrCursor(el) {
  	var bkgImage = _getStyle(el, 'background-image');
  
  	return bkgImage && bkgImage !== 'none' ? bkgImage : _getStyle(el, 'cursor');
  }
docs: When Firefox high contrast (colours override) option is enabled, "background-image" is overridden by the browser as "none". In that case, fallback to "cursor". But keep "background-image" as primary source because IE expects cursor URL as relative to HTML page instead of relative to CSS file.