Applying fullscreen to Telegram Mini App?

I am currently developing a Telegram Mini App, so basically a website which can be launched directly in Telegram by using a bot. I want the app to extend over the full screen size. Using the Telegram SDK and the window.Telegram.WebApp.expand() directive, I already achieved the expansion of the app to the top of the screen. On the bottom, however, the classic chat input field still remains and only disappears, when the WebApp.MainButton is enabled. I do not necessarily want to use the MainButton, but still have the app expanding all the way down, without showing the chat input.

Link to screenshot of my apps interface

I’ve seen it working for apps like NotCoin, TapSwap and Hamster Kombat, but as the code is not publicly available, I couldn’t reproduce this behaviour so far.

Link to TapSwap Interface screenshot

Does anyone know, how to achieve this?