dumb question about gadgets

Hi;

In another app I am writing, I BELIEVE gadgets used to come out stacked vertically. After an upgrade (to current git), I think they come out "diagonally," in that the x & y of successive gadgets increase (presumbly by the dimensions of its preceding gadget). Please find attached the simplest test program I could cons up that displays the behavior, along with a screenshot that shows the behavior.

What is the idiomatic/best way to get them to stack vertically? I messed about (again, mostly unsuccessfully, or I wouldn't be pestering you all) with various approaches, but every time I find myself with a complex solution, it turns out there is indeed a Better, Simpler Way.

Thanks,

-jm