Any Gantt chart can be placed onto a Jira Dashboard or embedded into a Confluence page as a read-only gadget.
The Structure.Gantt gadget has limited functionality and is mostly dedicated to viewing. It is not possible to alter a schedule or see task details using the gadget (users should continue to use Jira or Structure.Gantt for these tasks). Additionally, if your gadget is not refreshing or is not refreshing frequently enough, make sure you have properly configured your gadget's refresh interval. See Jira Dashboard Gadget for more details.