You can choose not to display a dashboard that you own under My Dashboards on the Navigation menu. For example, you may not want a shared dashboard to display under both My Dashboards and Public Dashboards.
To remove dashboards from My Dashboards:
On the Navigation menu, select a dashboard that you own.
On the Dashboard toolbar, click Remove from Menu.
If you want to add the dashboard back to My Dashboards, click Add to Menu on the Dashboard toolbar.
Learn about the Dashboard toolbar
Configure access control to dashboards