Allowing MessageBox when linked from social media on iOS

When a web app link is shared using social media like Linked-in or FaceBook,
the web app is restricted in terms of functionality;
the Xojo Web MessageBox is not showing, making all alerts and confirmations given by a Web MessageBox fail on iOS.
Does anyone know a way around this, so in effect a way to show WebApp Message boxes when the WebApp URL is shared from social media?
Or is the only safe way to avoid the MessageBox and add a View to show the message?
(that would be possible, but cumbersome)