Hi,
I'm trying to see what you want to do. My guess is that you want those 2 subforms to have a border, but, since they don't have the same height, you get an ugly line on the bottom of one of them (smallest) and you want that subform also to become as high as the other.
As far as I recall, this 0in is by default because you have a flowed subform. The height of the subform is determined by its content and therefore the function always give 0in.
Coming back to the problem, if I was correct guessing what you want to do, why not do this
1) border on your subform with flowed western text containing the 2 other subforms
2) only right border on the left subform inside the big one
3) only left border on the right subform inside the big one
This way, the borders will overlap and the biggest subform decides how tall the border is. You don't have a border on these inside subforms, but the outside subform takes care of it.
Tell me if that is what you need, otherwise, could you post a screenshot of what you want ?