In better news, I snuck in a little moe work this morning. I added 'use the rest' as a sizing option for the TableLayout. It's actually fairly complicated since it involves re-tying half of the columns/rows to calculate everything except the 'leftover' one rather than just assuming they come out right.
That change allowed me to redo the border widget to use the layout rather than the hackish non-reusable layouts I was using before. It's now much shorter, much more reusable, and a bit more configurable. Yay.