[Plugin: WebsiteChat.net Live Support] error message in wodgets screen

thereis error message in wodgets screen:
Notice: Undefined index: websitechat_submit in /home/juraj/work/www/wp331/wp-content/plugins/websitechatnet-live-support/websitechat-net.php on line 46

looks like very old code 🙁

http://ww.wp.xz.cn/extend/plugins/websitechatnet-live-support/