I’m not sure how to find this plug in. The others are listed when you are creating a new article, but I don’t see a button for the comparison tool. How can we embed that feature as well?
We are sorry to hear that you have such issues. We assume that you installed not appropriate plugin version for your Joomla CMS. Could you please double check that you installed plugin for the appropriate version of your Joomla CMS.
Here you will find Comparison plugin’s for different Joomla versions: http://joomlacode.org/gf/project/grpdocscompare/frs/
Please investigate plugin documentation for more details here: http://groupdocs.com/docs/display/Viewer/Integrating+the+Plugin+with+Joomla+2.5.11+Using+Default+Method