UMG Widget Border Box Background, Does not work.

I’ve just wrapped my inventory window in a default white border box. It looks like this is the editor:
However, once I load the game and my inventory windows are populated, I see that the inventories do not have the white background. Seems pretty simple, but why wouldn’t this work?

And here is the hierarchy of my different boxes in the editor. That Border box is just the default one that is generated upon creation. The InventoryGrid has the “white boxes” you saw in the screenshot before.

Figured it out, you also need to wrap all of that in a canvas panel and select “Size To Content” for some unknown arcane reason.