No fullscreen option when using embed code for Instant App

[JasonBatory]

I have an AGOL Instant App (Zone Lookup) embedded on a webpage using the embed code provided by the Instant App config, e.g.: 

<iframe src="https://[myOrg].maps.arcgis.com/apps/instant/lookup/index.html?appid=[myappID]" width="400" height="600" frameborder="0" style="border:0" allowfullscreen>iFrames are not supported on this page.</iframe>

However, there is no option in the app to make it fullscreen. See screenshot below.

Is this a known bug?

Regards,

Jason

[KellyHutchins]

In the web site where you embed the iframe you can add a link to open the web site in a new page. Here's one example of how this would work. 

<iframe src="https://jsapi.maps.arcgis.com/apps/instant/lookup/index.html?appid=924efc4b5e754b6cabfb81cbe81a099b" width="400" height="600" frameborder="0" style="border:0" allowfullscreen>iFrames are not supported on this page.</iframe>
<p><a href="https://jsapi.maps.arcgis.com/apps/instant/lookup/index.html?appid=924efc4b5e754b6cabfb81cbe81a099b">Open app fullscreen</a></p>