No full screen button on dashboard/reports shared with people outside organisation

Hi,

I share dashboards/reports with people outside my organisation but they can't view the reports in full screen mode because they don't have a full screen button in the upper right corner (see screenshot below)....and adding ' ?chromeless=1 ' to the url of their link doesn't work either.

Do people outside your organisation can't view the Power BI dashboards/reports in full screen mode, or does anyone know a solution?

Thanks in advance for your help!

Frank