Background page layout in OpenHAB Android app

I hope this is the right place for my question.

I’ve created some custom layout pages where I want to add a full screen background. Therefore I added the following code at the top of the page:

  label: Startpagina
    background-image: url(/static/backgrounds/one.png)
    background-size: cover

This is the default page where the Android app opens with. However, the background is not shown. It’s just white. When I add the exact same piece of code in a page which is linked from the default page via a popup, it works flawlessly.

Hope anyone can point me in the right direction for a fix or workaround or just to confirm that this is working as intended.