Foldable theme: widget icons pushed underneath header on mobile view

[KayceeFaunce]

We have an application that was built using version 2.22 of WAB for developers. I'm hoping there's a way to fix this by updating some of the code in the already deployed application rather than re-building this in a newer version of WAB.

When the application is displayed on a small screen/mobile, the ZoomSlider widget is hidden underneath the header and the home widget disappears - presumably also underneath the header. 

Desktop view:

Mobile view:

Any ideas how to fix this?