Documentation for JIRA 5.0. Documentation for other versions of JIRA is available too.
The Bugzilla Issue ID Search gadget allows you to search all JIRA issues for references to Bugzilla issue IDs. If the specified ID is not found within JIRA, the gadget redirects to the Bugzilla issue (if a Bugzilla server URL has been specified). This allows JIRA to become the one interface for all JIRA and Bugzilla issues.
Please note that this gadget does not work if the Bugzilla issues were imported using the JIRA Importers Plugin (which replaced the built-in JIRA importer at the release of JIRA 4.4). Instead, please use JIRA's Simple/Advanced Search to find your Bugzilla issue IDs.
The Bugzilla Issue ID Search gadget should appear as follows on the dashboard: