Bug with paste

When I paste code – for example:

$(this).wrap('<span class="radio-button"></span>');
     if ($(this).is(':checked')) {
           $(this).parent().addClass('on');
     }

Then span dont have class 🙁

$(this).wrap('<span></span>');

This is happend with all tags – div, span ect.

When i write this message, my version of this plugin is 1.7.3

http://wordpress.org/extend/plugins/wp-syntaxhighlighter/