Panel Form Layout in another Panel Form doesn't work

This works

af:SubForm
      |_PanelStretchLayout(center)
                  |_-PanelGroupLayout(scroll)
                                |_ -PanelBox/Panel Header
                                                |_ Panel Form Layout(can use fieldWidth=66% labelWidth=34%)

Best Practices
http://docs.oracle.com/cd/E18941_01/tutorials/jdtut_11r2_42/jdtut_11r2_42.html