Multi Level Cascade Select Plug in is a Plug In for the Atlassian Jira issue Tracker, that models a new custom field. The new custom field allows you to have a cascading select with a multi level selection.
After the download of the cascadingselect-VERSION-bundle.zip package, please copy all the files under WEB-INF directory to $ATLASSIAN_HOME/WEB_INF/. Simply extract the plug-in in the Jira Directory and the new Multi Level Cascading Select Custom Field will be added.
If you are upgrading from versions < 2.4, you need to rebuild the JIRA index (see here )