I've just stucked into the same problem as thread starter did
I've attached a simple demonstration. It's build with GWTP 0.7, GXT 3.0.1, GWT 2.4.0. What it does:
BasePresenter is the one which handles basic application layout. NestedPresenter is the one that provides content for 'center' widget of BorderLayoutContainer in BasePresenter's view.
NestedPresenter generates 50 rows of data for Grid and injects them into it when handling RevealContentEvent is handled.
If grid is inserted with VerticalLayoutData(1, -1) the grid ignores page's bottom border and flows deeply under it (no scrollbar is provided). If VerticalLayoutData(1, 1) is used, then Grid preserves some space for vertical scrollbar (it's differable from previous view's render results) but Grid's body is rendered with height: 0px style property. I couldn't trace into where height is calculated.