I have create a ContentPanel (RowLayout(Style.Orientation.VERTICAL)) with
1) VerticalPanel (RowData(1, -1))
2) ContentPanel (RowData(1, 1))
3) VerticalPanel (RowData(1, -1))
And when I render a main ContentPanel, only first VerticalPanel and ContentPanel are visible.
In Beta3 it was Ok setting FILL_BOTH for ContentPanel and FILL_WIDTH for VerticalPanels.