full screen button is missing in secured embedde power bi reports

when using secure bi embedded iframe via the power bi "Embbed" tab in my power bi report "full screen" icon is missing,

my embedding code is: https://app.powerbi.com/reportEmbed?

unlike when using a non secured reports embedding E.G:  

https://app.powerbi.com/view?

how can i enable the "full screen" button in my iframe secured embeddemnt reports?