How to navigate a scrollBox using a gamepad?

I have multiple button widgets inside the scrollBox.

When I start to navigate the scrollBox,

I have the focus on the first button and when I try to navigate to the next one,

it loses the focus and it seems like the navigation is jammed.

Is there a way to simply navigate inside the scrollBox?

This is strange. I have ScrollBox in my project and it works normally. Can you give us screenshot of your whole widget? Maybe we can help you better like that.