All users have access to the Manage Widget tab. On selecting the Manage Widget tab, the left pane displays all the Dashboards you have access to. When you select a Dashboard in the left pane, the Widgets from the selected dashboard are listed in the middle pane. Selecting a widget displays the widget layouts for the selected widget on the right pane.
The options available to you at a Dashboard, Widget and Widget layout level depend on whether you are the author of the dashboard, or have editor or viewer privileges to the dashboard.
Manage Widget options for Dashboard Author >>