In order to prevent DOS attacks on a JIRA instance, by creating a dashboard with 100s of gadgets and reloading the page, JIRA 4.0 will impose a limit on the number of gadgets users can add to a dashboard. If they try to exceed this limit they will get the following error message in a popup:

Sorry, you have exceeded the maximum number of gadgets supported by your Dashboard. You must remove some gadgets before proceeding.

By default, you're only allowed to have 20 gadgets per dashboard.

We should document that if admins really want to raise this limit, then they can edit the 'jira.dashboard.max.gadgets=20' jira-application.properties property, to a value that suits them (and restart JIRA).

On a side note: Old dashboards (from data prior to JIRA 4.0) that already have more gagdets on them than this limit, will still be displayed for backwards compatibility. The error message above will only be shown if the user tries to add yet another gadget to this dashboard.