PHP Notice: Undefined property: WidgetCache::$option_name

Thanks for a great plugin.

I want to report the following PHP notice:

PHP Notice:  Undefined property: WidgetCache::$option_name in
/wp-content/plugins/widget-css-classes/includes/widget-css-classes.class.php
on line 131

that’s filling up the debug logs. It looks like a conflict with the WP Widget Cache plugin?

I’m using the latest version (1.2.6) of the plugin and WP 3.9.1

Thanks.

https://ww.wp.xz.cn/plugins/widget-css-classes/