Undocumented Gwt-Ext BorderLayout behavior

BorderLayout manage widget into north, south, west, east and center
region. It will not lay widget correctly if widget in north or
south doesn't have specified height or widget in east or west
doesn't have specified width.

So keep in mind that:

1. Always set HEIGHT for widget in NORTH region
2. Always set HEIGHT for widget in SOUTH region
3. Always set WIDTH for widget in WEST region
4. Always set WIDTH for widget in EAST region