Overlapping Constraint Layout: Buttons not clickable

Question

I want to create a dynamic layout, in the mean that the parallel aligned piecharts (black circles) will be transformed into a diagonal alignment. And to give it even more height I want to wrap the filter bar (red rectangle) to orientate vertical instead of horizontal.

To accomplish that I'm using a constraint layout (blue rectangle) and vertical and horizontal guidelines(green) with 50 percent within the scrollview. The current issue I have is that the buttons within the filter bar (red rectangle) are not clickable,since they are overlapping (yellow surface) with the scrollview.

Why is that so? And how can I make them clickable? One solution would be to make the filter bar part of the scrollview, but the the filter bar would scroll away during scrolling. But I definitely want to keep the filter bar as it belongs contentwise to the first linear layout at the top of the screen.

This would work out, since I also have another filter bar (not part of the drawings) on the bottom for the piecharts which I then transform also from horizontal to vertical alignment. Guess this works because that filter bar is part of the same constraint layout (within the scrollview).

Other solution would be to algin the top of the scrollview only to the bottom of the red rectangle, but then I would not have gained any more height for the scrollview at all..