Virtual Keyboard on mobile browser hides content instead of pushing it up

Hello,

The mobile phone virtual keyboard hides content of the chat and the input text box, instead of pushing it up!.

Attach two screen shot that from the vanilla demo chat in:
https://botman.io/2.0/web-widget

Changing mobileHeight parameter don't solve the issue.

I checked it using several phones, mobile browsers and virtual keyboards type. All with the same problem.

It make the web widget unusable from mobile.