Plugin messes up with tinymce editor buttons

After enabling this plugin, tinymce rich text editor disappears.
After disabling it, tinymce buttons appears again.
No caching plugins installed.

These are errors in firebug console:

TypeError: ed.on is not a function
ed.on( 'BeforeSetContent', function( e ) {
in http://website.com/wp-content/plugins/sgr-nextpage-titles/admin/tinymce/js/plugin.min.js?ver=359-20131026 (line 33, col 4)

TypeError: this.getDoc(...) is undefined
...dy:function(){return this.bodyElement||this.getDoc().body},convertURL:function(o...
http://website.com/wp-includes/js/tinymce/tiny_mce.js?ver=359-20131026 (line 1, col 179650)

https://ww.wp.xz.cn/plugins/sgr-nextpage-titles/