Caching is on by default in most applications.
You can control caching as follows:
com.atlassian.gadgets.dashboard.ignoreCache to true or false.ignoreCache parameter to the URL, e.g. http://jira.example.com/jira/secure/DashboardV2.jspa?ignoreCache=false.If caching is on (e.g. ignoreCache is false), your gadget specs and locale files will not update right away when they change.
Writing an Atlassian Gadget
Gadgets and Dashboards Development Hub