An issue was reported whereby the Classic Dashboards cannot be modified when using a browser other than Internet Explorer. The blocks list does not render correctly, and the Add button does not work.
The Classic Dashboard admin interface was not updated for cross-browser compatibility, and will only be supported for clients using Internet Explorer. This screen will not be updated in a future release, as no further features will be added to the Classic Dashboard. The Sage CRM Support Matrix has been updated to reflect this.