Right under the resource list there is a panel labeled Latest Synchronizations. It displays information about how many new and changed topics appeared in resources during the last synchronization.

When you click a resource in the Latest Synchronizations panel, this resource will be opened, but only if new or changed topics were detected during the last synchronization. Otherwise, the resource will be removed from the Latest Synchronizations panel without the corresponding tab being opened.

When you close the tab of a resource, it is also removed from the Latest Synchronizations panel.