PropertyGroups with panel_widget are always shown before PropertyGroups without panel_widget
This issue was created automatically from an original Mantis Issue. Further discussion may take place here.
PropertyGroups in the proxy XML are not always displayed in the order they are defined. First, PropertyGroups that have panel_widgets defined are displayed. Then, property groups that are merely grouped together (and have no panel_widget specified) are displayed.
It would be better to display PropertyGroups as they are defined in the XML.