1. Go to the device page by clicking on it.
2. Go to the device settings by clicking settings tab above the chart.
3. Scroll down in the device settings page to the "Hide Device" section.
4. Toggle the "hidden" setting.
5. Go back to the dashboard and make sure you have something selected in the Filter.
6. If you need to un-hide the device, select "Hidden devices" from the filter dropdown, and repeat the steps above.