Comment 5 for bug 876299

Ok - so we weren't asking for any extra allocated vertical space, nor asking to expand into that which is allocated - presumably because we never allocate any extra size to that part of the dialog, and because the old GtkScrolledWindow implementation always requested enough size to fit the vertical scroll-bar, and that was enough to make things "work" until now.

I think the right fix here is to figure out a text-metric based minimum height for our text widget.