When clicking in a graph Customizer and select Export, it reloads the dashboard and nests the whole page within the content area.


WORKAROUND.
To export the contents of a graph using the Customizer, open the corresponding dashboard in Foglight classic web console.
To open Foglight classic web console, edit the URL to include the path /console next to the hostname in the URL. For example: https://foglightserver.example.com:8443/console
STATUS.
This issue has been logged as defect FOG-4788 and has been fixed in the 6.3.0.6 and higher releases of Foglight.