Buttons shifting down on a scroller?

I've been sort of tinkering around with the scroller tools, but there's something that I can't seem to solve.

When I have content that is smaller than the viewport itself, supposedly centered and fixed to the top, enter Play Mode, and click and drag the buttons, they shouldn't be moving, but for some reason, they shift downward. They then are rearranged that way in the scene view and remain that way before I have to move the content back to the top.

https://gyazo.com/08e45ca96a7b90a82f842846f03b1fd8

Is there any way to keep these buttons from shifting down to the middle of the viewport?